fokS,7 


The 

Manufacture,  Distribution 

and 

Use  of  Gas 

in 

Philadelphia 


A.  E.PATTOW 


Issued  by 

The  Educational  Committee  of  the  Philadelphia  Chamber 

of  Commerce 


Rejprint  of  Issue  of  191', 


Presented  to  the 


Schools  of  Philadelphia 
by 

The  United  Qas  Improvement 
Qompany 


I 


Educational  Pamphlet  No.  10,  issued  by  the  Educational  Committee 
of  the  Philadelphia  Chamber  of^Commerce 


Copyright,  1917,  Philadelphia  Chamber  of  Commerce 


U5H 
P  53m 

C.OJ.Z 


View  of  a  Portion  of  the  Philadelphia  Gas  Works  at  Passyunk  Avenue  and  Schuylkill  River 


3 


0 


Index 


Chapter  I. 

The  Beginning  of  the  Use  of  Illuminating  Gas 

Page 

No. 

Other  Products  from  Coal .  7 

Separating  the  Gas  from  the  By-Products .  7 

First  Use  of  the  Word  “Gas” .  8 

Formation  of  the  Gas  Company .  8 

Relation  of  the  Gas  Company  to  the  City .  9 

Composition  of  Coal  Gas .  9 

Chapter  II. 

Principles  Involved  in  the  Manufacture,  Distribution  and  Sale  of 
Illuminating  Gas 

Coal  Gas  Manufacture .  10 

Carburetted  Water  Gas .  13 

Process  for  Making  Carburetted  Water  Gas .  14 

Gasometer  or  Gas  Holder: 

Tank . . .  17 

Guide  Frame .  17 

Holder .  18 

Operation  of  Holder .  18 

How  the  quantity  of  gas  that  can  be  stored  may  be  increased  without  increasing  the 

size  of  the  holder  tank .  19 

Pressure  Gauge .  20 

Gas  Governor .  20 

Mains .  22 

Service  Pipes .  24 

Meter .  24 

Meter  Pro ver .  27 

How  to  Read  a  Meter .  27 

Methods  of  Using  Gas .  28 

Welsbach  Lamp .  .  32 

Services  of  the  Gas  Company .  41 

Complaint  Men .  41 

New  Business .  41 

Chapter  III. 

Philadelphia  Gas  Works .  44 

Appendix 

Photometer .  53 

Calorimeter .  5  7 

4 


Illustrations 


Figure  Page 

No.  No. 

1  Simple  Form  of  Coal  Gas  Retort .  10 

2  Simple  Form  of  Coal  Gas  Retort .  10 

3  Benches  of  Nine  Retorts  each  in  a  Gas  Works .  12 

4  Coal  Gas  Generating  Apparatus .  13 

5  Water  Gas  Generating  Apparatus .  14 

6  One-section  Gas  Holder .  17 

7  Two-section  Telescopic  Gas  Holder .  19 

8  Pressure  Gauge  and  Bell  and  Spigot  Pipe  Joint .  20 

9  Simple  Form  of  Gas  Governor .  21 

10  Dry  Gas  Meter  (Case) .  25 

11  Mechanism  for  Operating  Dry  Gas  Meter .  25 

12  Measuring  Compartment  and  Valves  of  Dry  Gas  Meter .  26 

13  Explanation  of  the  Gas  Meter  Dial .  28 

14  Lava  Tip  Gas  Burner .  29 

15  Water  Heater,  Showing  Proper  Combustion  of  Gas  by  Use  of  Bunsen  Burner.  .  30,  31 

16  Details  of  Mixer,  Bunsen  Principle .  31 

17  Same  Type  of  Mixer  Adapted  to  Use  on  Gas  Cooking  Stoves .  31 

18  Upright  Mantle .  32 

19  Inverted  Mantle .  33 

20  Details  of  Inverted  Mantle  Light .  34 

21  Larger  Size  Inverted  Mantle  Lamp .  35 

22  Upright  Bunsen  Burner  with  Inverted  Mantles .  36 

23  Gas  Engine .  38 

24  Test  of  High  Pressure  Water  System;  Power  Supplied  by  Use  of  Internal  Combus¬ 

tion  Gas  Engines .  39 

25  Illuminating  Gas,  after  Mixture  with  Oxygen,  being  used  for  Welding  Purposes.  ...  40 

26  Quick-Service  Man .  42 

27  Gas  Holder  Station .  45 

28  Laying  Large  Gas  Mains  in  City  Streets .  48 

29  Gas  Photometer .  53 

30  Disc  Box .  54 

31  Details  of  Disc  Box  and  Sight  Piece .  55 

32  Sight  Piece  "K” .  56 

33  Junker’s  Type  Calorimeter .  57 

34  Details  of  Junker’s  Type  Calorimeter .  59 


5 


Digitized  by  the  Internet  Archive 
in  2017  with  funding  from 

University  of  Illinois  Urbana-Champaign  Alternates 


https://archive.org/details/manufacturedistr00phil_0 


The  Beginning  of  the  Use  of 
Illuminating  Qas 

% 

ABOUT  the  year  1792  an  English  engineer  put  a  piece  of  soft  coal  in 
the  bowl  of  a  clay  pipe.  He  filled  the  bowl  of  the  pipe  on  top  of  the 
coal  with  a  plug  of  clay  so  that  no  air  could  get  to  the  coal.  He 
then  put  the  bowl  of  the  pipe  upside  down  in  a  fire,  leaving  the  stem  sticking 
out.  When  the  bowl  of  the  pipe  was  red  hot  he  found  that  gas  was  pouring 
from  the  stem  and  that  when  lighted  it  gave  a  rich,  luminous  flame.  When 
the  gas  had  ceased  pouring  from  the  stem  he  took  the  bowl  out  of  the  fire, 
removed  the  clay  and  found  that  his  lump  of  coal  had  changed  its  shape 
and  had  been  converted  into  a  piece  of  coke,  which  he  found  to  consist  of 
pure  carbon  and  some  ash. 

The  lump  of  coal  had  been  made  hot  enough  to  burn  if  oxygen  had  been 
present  with  it,  but  all  air  had  been  kept  away  by  the  plug  of  clay.  Instead 
of  burning,  the  coal  had  become  red  hot  and  had  first  melted  to  a  plastic 
and  sticky  mass  from  which  came  off  bubbles  of  what  seemed  to  be  a  dense, 
smoky  gas.  The  melted  coal  then  hardened  to  red,  porous  coke  which  still 
gave  off  gas  in  diminishing  quantity  until  there  was  left  nothing  but  a  lump 
of  hot  coke,  which,  after  removal  and  cooling,  became  a  gray  coke  with  a 
shining  luster. 

OTHER  PRODUCTS  FROM  COAL : 

This  gas  coming  from  the  coal,  if  allowed  to  flow  out  unlighted,  still  hot 
from  the  end  of  the  stem  of  the  pipe,  would  have  been  found  to  be  black 
and  smoky  with  a  strong  odor  of  tar.  It  would  not  be  in  the  same  condition 
as  the  pure,  colorless  gas  which  the  consumer  finds  coming  from  his  burner, 
but  would  contain  in  addition  to  that  gas  a  number  of  other  materials  such 
as  tar,  steam,  ammonia,  cyanogen,  lamp-black,  benzols,  and  vapors  of  other 
oils  consisting  of  carbon  and  hydrogen  in  chemical  combination  with  each 
other,  gases  of  sulphur  and  carbon,  other  gases  of  sulphur  and  hydrogen 
and  carbon  and  oxygen. 

To  the  gas  manufacturer  these  additional  substances  are  known  as 
by-products  of  coal-gas  manufacture.  The  gas  must  be  cleaned,  then,  before 
it  leaves  the  gas  works.  If  this  is  not  done  some  of  these  by-products 
would  condense  in  the  mains,  form  stoppages  and  reduce  the  rate  of  flow 
of  gas.  Other  vapors  and  mists  would  carry  longer  distances  and  there 
condense,  and  again  here  and  there  in  the  smaller  pipes  and  in  the  burners 
the  stoppages  would  shut  off  the  flow  of  gas;  and  even  when  the  gas  arrived 
at  the  consumer’s  house  and  was  burnt,  the  air  would  be  contaminated  with 
burnt  impurities  that  would  cause  serious  inconvenience  and  discomfort 
in  breathing  and  would  be  disagreeable  in  other  ways. 

SEPARATING  THE  GAS  FROM  THE  BY-PRODUCTS: 

The  removal  of  all  of  these  impurities  is  accomplished  in  the  gas  works 
by  a  system  of  carefully  cooling  the  gas  in  condensers  or  coolers,  then  wash¬ 
ing  the  gas  in  contact  with  cold  water,  and  finally  by  forcing  the  gas  through 
purifiers  to  remove  that  portion  which  when  burnt  would  cause  distress  to 
the  people  present  .  7 


8  The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


While  we  are  now  dealing  only  with  illuminating  gas,  it  is  well  to  say 
here  that  these  other  products,  from  which  the  illuminating  gas  must  be 
freed  before  it  can  be  used,  form  a  most  interesting  and  valuable  group  of 
materials  for  the  use  of  man.  From  them  are  made,  by  chemical  processes 
(some  of  which  are  long  and  difficult,  requiring  knowledge  and  skill  pos¬ 
sessed  by  few),  a  great  number  of  aniline  dyes,  many  drugs  and  medicines, 
explosives,  perfumes,  disinfectants,  germicides  and  creosotes,  materials  for 
ice  making,  road  making,  roofing  and  a  great  list  of  other  materials  used 
in  the  trades,  arts  and  sciences. 

The  production  from  black  tar  of  pure  white  saccharin,  a  substance 
having  a  sweetening  effect  five  hundred  times  that  of  the  same  weight  of 
sugar,  is  a  single  illustration  of  the  many  unexpected  uses  that  have  been 
found  for  these  materials. 

FIRST  USE  OF  THE  WORD  GAS: 

Long  before  the  period  when  illuminating  gas  was  first  exhibited, 
about  1797,  it  was  known  that  there  existed  and  could  be  produced  gases 
differing  very  greatly  in  their  properties  from  the  mixture  of  nitrogen  and 
oxygen  that  forms  our  atmosphere.  About  the  year  1600  Van  Helmont  in 
his  writings  shows  that  he  was  aware  of  these  other  gaseous  materials  and 
he  called  them  “spirit,”  using  the  German  word  “geist”  (meaning  spirit), 
and  from  this  the  word  “gaz”  (French),  or  “gas”  (English)  came  into  use. 
His  idea  appears  to  have  been  that  this  spirit  or  “geist”  could  be  reduced 
into  solid  form,  and  that  many  solid  bodies  were  made  up  almost  entirely 
of  this  spirit.  Later,  other  experimenters  learned  more  and  more  about 
the  different  gases  until  our  forefathers  of  one  hundred  years  ago,  under 
the  leadership  of  William  Murdock,  first  realized  that  the  material  coming 
off  the  coal  contained  good  illuminating  gas,  from  which  the  heavy  by¬ 
products  could  be  separated,  leaving  the  gas  itself  to  be  passed  through  miles 
of  pipe  without  losing  in  value.  They  did  not  at  once  realize  the  full  force 
of  what  this  conversion  of  coal  into  gas  meant  to  mankind.  It  took  them 
almost  twenty  years  to  put  in  force  this  new  idea. 

FORMATION  OF  THE  GAS  COMPANY: 

That  idea  was:  Instead  of  each  householder  going  out  to  replenish 
his  supply  of  candles  or  oil  for  lighting,  of  wood  or  coal  for  heating  and 
cooking,  why  not  bring  the  coal  or  wood  (for  wood  when  plentiful  was 
formerly  used  for  gas  making)  into  some  place  in  or  near  the  city,  there 
convert  it  into  gas  and  force  the  gas  through  pipes  laid  in  the  streets  and 
houses,  so  that  when  light  or  heat  was  wanted  it  was  only  necessary  to  turn 
a  valve  and  apply  a  lighted  match? 

To  do  this  required  the  building  of  a  gas  plant  and  for  this  a  company 
was  formed  and  stock  sold  to  provide  money  for  installing  the  entire  plant. 
This  required  the  use  of  the  city  streets  for  laying  the  distribution  mains. 
If  a  gas  works  had  been  provided  within  each  of  the  city  blocks  it  would 
not  have  been  necessary  to  cross  the  city  streets  with  mains,  but  as  this,  of 
course,  was  impossible  for  many  reasons  the  use  of  the  streets  became  abso¬ 
lutely  necessary  and,  since  the  streets  are  owned  by  the  city,  the  consent 
of  the  city  authorities  had  to  be  obtained  for  laying  the  pipes  in  them  for 
distributing  the  gas.  This  permission  is  called  a  “franchise”  and  no  com¬ 
pany  or  person  not  possessing  such  a  franchise  may  open  the  streets  to  lay 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia  9 


pipe  for  any  purpose.  Those  companies  to  whom  such  franchises  are  given 
and  who  use  the  streets  below,  on  or  above  the  surface,  are  in  turn  required 
to  sell  their  products  to  any  and  all  of  the  general  public  who  comply  with 
necessary  rules,  and  such  companies  are  known  as  public  service  companies 
or  corporations. 

Accustomed  as  we  are  to  its  benefits,  it  is  not  easy  for  us  to  realize 
what  a  change  came  into  the  lives  of  human  beings  through  this  century-old 
idea  of  introducing  gas  for  household  uses, — or  what  it  meant  in  saving 
of  labor  and  of  time,  in  equalizing  temperatures  so  that  the  cold,  cheerless 
room  became  cozy  again,  and  the  stifling  kitchen  became  a  pleasant  place 
to  work  in;  of  the  elimination  of  dust,  dirt,  odors,  and  lamp  dangers; 
of  its  immense  meaning  to  the  race  in  its  invitation  to  improved  cookery! 

And  when  we  consider  the  great  advances  in  the  industries,  sciences 
and  arts  due  to  new  discoveries  and  uses  of  other  residuals  from  the  dis¬ 
tillation  of  coal,  we  may  truthfully  say  that  the  Nineteenth  Century,  excel¬ 
ling  as  it  did  all  previous  periods  in  adaptation  of  newly  discovered  laws  of 
physics  and  chemistry  to  the  benefit  of  mankind,  contains  no  more  important 
event  than  the  development  due  to  the  distillation  of  bituminous  or  soft  coal 
for  gas  making  and  the  use  of  the  by-products  in  the  arts  and  sciences. 

RELATION  OF  THE  GAS  COMPANY  TO  THE  CITY: 

The  city,  representing  all  the  people,  gives  to  the  gas  company  the 
use  of  the  streets  for  distributing  mains,  protects  the  company  against 
competition  and  thereby  becomes  an  interested  party  in  the  gas  business. 

How,  then,  can  the  city  be  sure  that  the  gas  company  will  do  its  duty 
in  giving  a  good  quality  of  gas  at  a  fair  price  and  a  good  supply  to  all  the 
houses?  And  how  can  the  gas  company  be  sure  that  laws  will  not  be  passed 
hastily  and  through  ignorance  of  the  business,  that  will  put  unnecessarily 
heavy  burdens  on  the  gas  company? 

In  the  last  100  years  of  dealings  between  the  gas  companies  and  the 
public  many  methods  of  solving  these  problems  have  been  tried,  some  of 
which  have  been  found  good  and  others  complete  failures.  At  the  present 
time  in  many  states,  including  Pennsylvania,  all  such  questions  are  referred 
to  a  body  of  men  appointed  by  the  Governor  and  known  as  the  Public  Service 
Commission.  These  men,  giving  all  their  time  to  the  questions  of  rates  and 
the  business  of  public  service  corporations  and  being  acquainted  with  all 
the  laws  and  the  principles  involved  in  conducting  the  business,  stand  as  a 
court  of  appeal  before  which  the  corporations,  the  consumers  and  the  general 
public  may  lay  their  grievances. 

COMPOSITION  OF  COAL  GAS: 

Illuminating  gas  made  from  soft  coal  is  a  mixture  of  a  number  of 
simpler  gases  and  a  minute  percentage  of  vapors.  Some  of  these  gases  in 
burning  give  heat  and  no  light,  such  as  hydrogen  and  carbon  monoxide; 
others  give  great  heat  and  little  light,  such  as  methane;  others  give  both 
great  heat  and  great  light,  such  as  naphthaline;  others  give  a  comparatively 
small  amount  of  heat  but  are  of  great  illuminating  value,  such  as  benzine; 
still  others  give  neither  light  nor  heat,  such  as  carbon  dioxide,  oxygen  and 
nitrogen.  These  last  are  unavoidably  present  in  very  small  percentages  of 
the  whole. 


Principles  Involved  in  the 
l Manufacture ,  Distribution  and  Sale  of 
Illuminating  Qas 
v 

COAL  GAS  MANUFACTURE: 

In  the  gas  works  the  bowl  of  the  pipe  becomes  a  retort  and  Figures  1 
and  2  show  a  simple  retort  and  method  of  heating: 


FIG.  2 

Simple  Form  of  Coal  Gas  Retort 


10 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia  11 


The  lid  “L”  is  taken  off  the  cast  iron  mouthpiece  “M,”  which  is  fastened 
to  the  retort  “R.”  The  coal  “C”  is  then  charged  into  the  retort  by  shovels 
or  machinery.  The  retort  “R,”  having  one  opening  at  the  front  end,  is 
made  of  fire  clay  so  that  it  can  be  kept  for  several  years  at  a  bright  orange 
heat  without  melting,  bending  or  breaking.  After  the  retort  is  charged, 
the  lid  “L”  is  replaced  on  the  mouthpiece  “M”  and  then  there  is  no  way 
for  the  gas  from  the  heated  coal  to  escape  except  through  the  ascension  pipe 
“S,”  the  upper  end  of  which  curves  downward  to  dip  into  water  in  the  gas- 
tight  trough  “V.”  This  trough,  called  a  “hydraulic  main,”  receives  the  gas 
and  a  pipe  leading  from  it  is  connected  to  an  exhauster  which  draws  the  gas 
away  as  fast  as  it  is  made.  By  dipping  the  pipe  from  each  retort  into  the 
water  in  the  hydraulic  main  no  gas  can  go  backward  through  the  ascension 
pipe  “S”  when  the  lid  “L”  is  removed  from  the  mouthpiece  “M.” 

A  coke  fire  is  kept  burning  upon  the  furnace  grate  “G”  and  the  heated 
gases  therefrom  pass,  as  shown  by  the  arrows,  around  the  outside  of  and 
completely  enveloping  the  retort  “R”  which,  becoming  heated  and  remaining 
heated,  transmits  the  heat  through  its  wall  to  the  coal  “C”  inside.  The 
draft  of  the  fire  on  grate  “G”  can  be  controlled  by  the  damper  “D.” 

After  the  gas  has  stopped  coming  from  the  coal,  the  lid  “L”  is  opened 
and  the  coke  remaining  in  the  retort  is  withdrawn  through  the  mouthpiece 
“M;”  a  portion  of  this  coke  needed  to  maintain  the  fire  on  the  grate  “G” 
is  then  charged  into  the  furnace  and  the  balance  is  cooled  with  water  and 
carried  off  to  be  sold  or  used  in  other  places. 

The  charging  of  a  retort  is  done  at  regular  intervals  and  the  amount 
of  coal  is  carefully  weighed  for  each  charge.  The  retort  as  shown  here 
would  be  about  nine  feet  long,  contain  about  350  pounds  of  coal  and  would 
be  charged  every  four  hours.  Other  forms  of  retorts  in  use  will  hold  more 
coal  and  be  charged  at  longer  intervals.  Some  hold  as  much  as  fifteen  tons  of 
coal  and  are  charged  only  once  in  twenty-four  hours.  Figures  1  and  2  show 
the  simplest  form  of  single  retort  and  would  not  be  found  in  a  present-day 
gas  works  in  a  single  setting  as  shown  in  the  illustration.  In  the  gas  works 
a  number  of  retorts  are  heated  by  one  fire,  sometimes  as  many  as  sixteen. 
The  present  method  of  heating  such  retorts  is  not  as  simple  as  here  shown 
but  far  more  efficient  in  the  saving  of  heat. 

A  setting  of  a  number  of  retorts  heated  by  one  fire  is  called  a  “bench,” 
and  the  benches  are  set  side  by  side  in  a  gas  works  as  shown  in  Figure  3, 
there  being  nine  retorts  in  each  bench  shown. 

Where  a  large  number  of  retorts  are  thus  stacked  together,  they  are 
discharged  and  changed  in  successive  order  so  that  the  flow  of  gas  from 
the  hydraulic  main  “V”  is  continuous.  Some  of  the  tars  and  other  materials 
will  start  to  drop  out  in  the  hydraulic  main  “V”  and  the  removal  of  the 
balance  of  these  materials  must  be  started  at  once  before  the  gas  cools 
further. 

A  pump  called  an  “exhauster”  draws  the  gas  from  the  hydraulic  main 
and  forces  it  first  into  the  condenser  where  it  passes  downward  through  a 
number  of  tubes  which  are  surrounded  by  water  and  where  by  cooling  it  is 
separated  from  its  tar  and  steam  and  some  of  the  heavy  oils;  thence  upward 
through  the  scrubber,  consisting  of  a  number  of  wooden  trays,  where  it  is 
brought  in  contact  with  a  stream  of  water  passing  downward  over  the  wetted 
surfaces,  where  the  gas  gives  up  its  ammonia  to  the  water;  thence  the  gas 


12  The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


Benches  of  Nine  Retorts  Each  in  a  Gas  Works 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


13 


passes  to  the  purifier  where  certain  sulphurous  impurities  are  removed  by 
contact  with  oxide  of  iron  (this  is  necessary  because  if  allowed  to  remain 
in  the  gas  they  would  cause  discomfort  and  sore  throat  to  people  breathing 
the  air  in  the  room  in  which  the  gas  was  burned);  thence  through  the 
station  meter,  where  the  amount  of  gas  made  is  registered;  thence  into  the 
holder.  The  material  which  is  separated  from  the  gas  in  the  condenser 
flows  out  of  the  bottom  of  the  condenser  to  a  water-sealed  pot  (not  shown) 
whence  it  goes  to  the  tar  storage. 

The  material  removed  by  the  water  in  the  scrubber  flows  from  the 
bottom  of  the  scrubber  into  a  water-sealed  pot  (not  shown)  and  is  conveyed 
to  the  ammonia  well. 

CARBURETTED  WATER  GAS: 

There  is  one  other  way  of  making  illuminating  gas  which  will  contain 
all  the  individual  valuable  gases  contained  in  purified  coal  gas. 

While  the  coal  gas  is  made  by  breaking  up  (through  the  agency  of  high 
temperature,  called  destructive  distillation)  the  chemically  complex  coal 
into  a  number  of  simpler  parts,  of  which  gas  is  one,  water  gas  is  made  by  a 
building  up  or  synthetic  process  in  which  some  of  the  component  gases  are 
made  in  one  operation,  others  in  another  operation  and  all  are  mixed 
together. 

If  a  deep  bed  of  fuel  such  as  coke,  or  anthracite  coal,  is  burned  by 
forcing  air  under  pressure  through  it,  the  products  of  combustion  arising 
from  the  fuel  will  be  found  to  be  inflammable  if  burned  while  still  hot  by 
mixing  them  with  additional  air.  This  inflammable  gas  may  thus  be  used 
to  heat  a  mass  of  open  firebrick,  laid  with  openings  between  the  brick  and 
built  up  in  superposed  layers*  and  because  of  its  cross-sectional  appearance 
known  as  checker-brick. 

If,  when  the  bed  of  fuel  and  checker-brick  gets  highly  heated,  the 
admission  of  air  is  stopped  and  steam  instead  is  passed  through  the  hot 
coal  or  coke  the  steam  will  be  decomposed,  its  oxygen  will  unite  with  the 
carbon  of  the  coal  forming  carbon  monoxide,  its  hydrogen  will  be  set  free, 
and  these  two  gases  (CO  and  H)  will  be  given  off  the  top  of  the  fuel  bed. 
These  are  called  blue  gases  because  while  they  give  off  heat  in  burning,  they 
burn  with  a  small  blue  flame  and  give  only  enough  light  to  show  that  they 
are  burning. 

Hence,  in  order  to  insure  a  luminous  quality  to  water  gas,  other  gases 
are  introduced  at  this  point  by  the  process  called  carburetting.  These  two  hot 


14 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


inflammable  but  unburned  gases  are  passed  through  the  hot  open  brickwork, 
and  at  the  same  time  crude  oil  is  showered  down  upon  it.  This  oil  is  first 
vaporized  and  in  further  heating  by  passage  through  the  brickwork  its  vapors 
are  converted  into  fixed  gases  having  luminous  value  which,  even  when  later 
cooled  to  atmospheric  temperatures,  will  not  condense  back  to  liquid  but, 
remaining  gaseous  and  in  mixture  with  the  blue  gases  from  the  fire,  will 
pass  from  the  apparatus  as  crude  carburetted  water  gas.  Some  portions  of 
the  oil,  small  in  proportion  to  the  total  quantity  used,  will  be  converted  into 
tar  instead  of  gas  and  the  gas  must  be  separated  from  these  vapors  of  tars 
by  cooling  and  washing.  After  this  has  been  done  the  gas  must  be  purified 
of  its  sulphurous  constituents  by  passing  it  through  purifiers  as  in  the 
purification  of  coal  gas  previously  described. 

Figure  5  shows  the  process  for  making  carburetted  water  gas. 


The  anthracite  coal  or  the  coke  is  contained  in  the  generator  “G”  which 
is  filled  to  the  height  of  about  seven  feet  above  the  grate;  firebrick  is  placed 
checker  fashion  in  the  chamber  “C”  and  also  in  the  taller  chamber  “S.” 
Air  is  forced  through  a  pipe  called  the  air  blast  main  shown  dash-lined 
under  the  generator  and  can  be  led  as  desired  (1)  into  the  bottom  of  the 
generator,  (2)  into  the  top  of  the  chamber  “C,”  called  the  carburetter,  and 
(3)  into  the  bottom  of  the  chamber  “S,”  called  the  superheater.  Each  air 
inlet  is  controlled  by  a  valve. 

The  fire  in  the  generator  being  started,  and  the  stack  valve  “V”  at 
the  top  of  “S”  being  opened,  air  is  admitted  to  the  bottom  of  the  generator 
“G”  and  the  heating  of  the  fuel  proceeds.  As  soon  as  the  fuel  gets  heated 
to  a  bright  red  heat,  the  gases  coming  from  the  top  of  the  fuel  bed  and 
passing  over  into  the  carburetter  “C”  can  be  burned  if  mixed  with  more 
air.  This  is  done  by  opening  the  air  blast  valve  “B,”  following  which  the 
firebrick  in  the  carburetter  “C”  begins  to  get  hot  and  the  combined  burning 
of  these  gases  carries  over  into  the  superheater  “S”  and  finally  the  burned 
gases  pass  out  through  the  stack  valve  “V.” 

If  the  blast  valve  “B”  at  the  top  of  the  carburetter  is  opened  wide 
all  the  gas  can  be  burned  in  the  carburetter  which  would  then  heat  up 
rapidly,  but  if  it  is  opened  only  slightly  some  of  these  gases  will  not  get 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia  15 


air  enough  to  burn  until  they  meet  with  that  air  which  is  admitted  and 
regulated  through  the  valve  in  the  lower  part  of  the  superheater.  Thus 
the  operator,  by  care  in  the  amount  of  air  he  admits  to  each,  can  have  the 
heating  of  the  carburetter  and  superheater  proceed  as  he  desires. 

The  apparatus  so  far  has  not  been  making  illuminating  gas  but  has 
been  getting  its  brickwork  and  fuel  into  a  temperature  condition  to  make 
it.  When  the  heat  in  the  fuel  bed  and  carburetter  and  superheater  has 
reached  the  proper  degree 

The  air  valves  are  all  closed  tightly. 

The  stack  valve  “V”  is  closed. 

Steam  is  turned  into  the  bottom  of  the  generator  and 
passing  upward  through  the  highly  heated  carbon, 
flows  over  into  the  carburetter  top,  no  longer  as  steam 
but  as  carbon  monoxide  and  hydrogen. 

The  oil  valve  “O”  is  now  opened  and  oil  is  sprayed  down 
over  the  brickwork,  vaporizing  instantly  and  absorbing 
heat  from  the  bricks,  thus  lowering  their  temperature. 
This  cooling  effect  continues  until  unvaporized  oil  is 
carried  over  to  the  bottom  of  the  superheater,  at  which 
time  gas  making  should  cease.  In  any  case,  when  the 
oil  is  vaporized,  it  heats  up  rapidly  and  undergoes  an¬ 
other  important  change.  It  will  become  “cracked”  or 
“broken;”  that  is,  it  will  change  from  a  vapor  that 
would  upon  cooling  again  become  liquid  into  a  number 
of  simpler  gases,  which  on  cooling  will  remain  as 
gases,  except  a  small  portion  which  will  become  tar. 

This  operation  of  “cracking”  the  oil  whereby  the  molecules  of  the  oil 
are  broken  up  and  rearrange  themselves  into  simpler  molecules  is  similar 
to  the  destructive  distillation  of  gas  coal  previously  described  in  the  coal 
gas  process. 

The  gases  from  the  generator  give  no  light  and  but  moderate  heat,  the 
oil  provides  the  gases  that  give  both  high  heat  and  great  light  and  the 
methane  that  gives  little  light  and  great  heat. 

So  is  water  gas  built  up. 

As  to  the  balance  of  the  process: 

The  stack  valve  “V”  being  closed,  the  gas  reaching  the  top  of  the 
superheater  in  a  very  hot  condition  must  be  cooled.  It  passes  down  through 
the  pipe  “M”  to  the  wash-box  “W”  where  it  bubbles  through  a  water  seal 
so  devised  as  to  prevent  a  return  flow  of  gas,  thence  to  the  scrubber  “K” 
filled  with  wooden  open  trays  up  through  which  the  gas  passes  against  water 
showered  into  the  top  of  the  scrubber.  By  this  means  the  gas  is  washed 
clean  from  its  tar  and  carbon  particles,  for  whenever  an  oil  is  “cracked” 
there  is  liberated  some  fine  carbon  which  floats  as  lamp-black  in  the  gas. 
Thence  the  gas  passes  to  the  condenser  “Y”  where  it  is  cooled  by  water 
surrounding  the  condenser  tubes,  the  gas  passing  down  through  the  tubes. 
A  constant  stream  of  cold  water  enters  the  bottom  of  the  condenser  at  “X” 
and  the  hot  water  passes  out  through  the  overflow  near  the  upper  tube  sheet 
to  the  top  of  the  scrubber. 


First: 
Second : 
Third: 


Fourth : 


16  The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


In  the  condenser  the  tar  vapor  accompanying  the  gas  is  cooled  into 
liquid  tar,  which  flows  out  of  the  bottom  through  a  pipe  dipping  down  into 
the  liquid  tar  in  the  pot  to  prevent  the  escape  of  gas. 

From  the  condenser  the  gas  passes  direct  to  a  holder  “H,”  called  the 
relief  holder. 

The  process  of  making  water  gas  results  in  the  cooling  of  the  fuel  bed 
and  brickwork.  The  steam  in  passing  through  the  fuel  rapidly  cools  it  to 
a  temperature  at  which  the  oxygen  will  not  properly  combine  with  carbon, 
and  the  passage  of  the  oil  over  the  brickwork  rapidly  reduces  the  temperature 
below  that  temperature  needed  to  properly  “  crack  ”  the  oil  vapors.  It  then 
becomes  necessary  to  stop  making  gas  and  this  is  done  by: 

First:  Shutting  off  the  oil  flowing  into  the  carburetter. 

Second:  Shutting  off  the  steam  flowing  into  the  bottom  of  the 
generator. 

Third:  Opening  the  stack  valve  “V.” 

If  it  is  necessary  to  add  fuel  to  the  generator  it  is  done  at  this  period 
of  the  cycle;  the  door  at  its  top  is  opened  and  the  fuel  is  shovelled  or  poured 
in.  The  ashes  are  removed  from  the  door  low  down  on  the  side. 

Neither  of  these  operations  is  required  each  time  the  gas  making 
is  stopped,  so  that  usually  the  next  step  is  to  proceed  with  the  reheating  as 
previously  described. 

Water-gas  making  is  a  process  wherein  the  apparatus  is  alternately 
heated  by  combustion  with  air  during  which  time  no  illuminating  gas  is 
collected,  and  cooled  by  the  steam  and  oil  during  which  time  gas  is  collected 
but  no  air  is  admitted.  One  complete  cycle  of  gas  making  occupies  about 
eight  to  ten  minutes. 

After  the  gas  reaches  the  relief  holder  in  an  unpurified  condition,  it 
is  pumped  from  that  holder  by  the  exhauster  and  forced  through  the  puri¬ 
fiers,  the  large  station  meters  and  thence  into  the  storage  holders. 

The  term  “water  gas”  is  confusing  to  many,  who  have  fancied  that  in 
some  mysterious  way  a  combustible  gas  was  manufactured  from  water  only. 
While  some  water  in  the  form  of  steam  is  used  in  its  manufacture,  this 
water  does  not  exist  in  the  finished  gas  and  is  only  used  as  above  described 
in  one  step  of  gas  making. 

There  is  at  present  more  water  gas  than  coal  gas  made  by  American 
gas  companies. 

Water  gas  production  is  not  accompanied  with  the  large  number  of 
by-products  which  will  always  be  found  when  bituminous  coal  is  distilled 
to  make  coal  gas.  There  are,  however,  some  very  valuable  products  re¬ 
sulting  from  water  gas  manufacture  which  are  coming  into  use  in  many 
of  the  industries. 


Gasometer 


nt 


Figure  6  shows  a  simple  one-section  gas  holder  or  gasometer  and  is 
here  represented  as  if  filled  with  gas.  It  consists  of  a  tank  “A,”  guide 
frame  “B,”  and  holder  “C.” 


THE  TANK  “A”: 

This  is,  as  shown  in  Figure  6,  a  pit  sunk  in  the  ground  and  made 
water-tight,  by  masonry  or  concrete  walls  on  the  sides  and  bottom.  Ex¬ 
tending  up  through  the  water-tight  bottom  and  reaching  above  the  level 
of  the  water  in  the  tank  are  the  gas  inlet  pipe  “D”  and  the  gas  outlet  pipe 
“E.”  Built  into  the  bottom  and  located  at  equal  distances  around  the 
bottom  edge  of  the  tank  are  “landing  blocks”  on  which  the  holder  lands 
when  empty.  Vertical  guide  rails  made  of  steel  are  secured  to  the  side 
walls  of  the  tank  and  are  equally  spaced  around  the  walls  and  form  tracks 
or  guides  for  the  guide  wheels  fastened  to  the  bottom  edge  of  the  holder. 

THE  GUIDE  FRAME  “B”: 

This  consists  of  a  number  of  vertical  columns  equally  spaced  and  resting 
on  the  top  of  the  side  walls  of  the  tank.  The  columns,  usually  built  of 
steel,  are  connected  to  each  other  by  horizontal  girders  and  form  a  strong, 
wind  resisting  framework  extending  above  and  enclosing  the  tank.  Each 
column  has  for  its  inner  face  a  guide  rail  exactly  vertical  which  forms  the 
track  for  the  guide  rollers  on  top  of  the  holder.  17 


18 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


THE  HOLDER ,  PROPER ,  “C”: 

This  consists  of  an  inverted  cup  built  of  sheets  of  steel  riveted  together 
and  having  a  gas  tight  top  or  crown  and  a  heavy  rim  of  angle  iron  around 
the  bottom.  It  is  open,  of  course,  at  the  bottom.  Fastened  to  the  bottom 
angle  iron  are  brackets  which  carry  rollers  engaging  with  the  vertical  guide 
rails  fastened  to  the  sides  of  the  tank,  while  the  rollers  shown  above  the 
edge  of  the  top  engage  with  the  guides  on  the  columns.  In  this  way  the 
holder  is  kept  level  while  rising  and  falling  according  to  the  quantity  of  gas 
it  contains.  The  rollers  on  the  bottom  are  so  placed  as  to  avoid  striking  the 
landing  blocks  when  the  holder  is  “landed.” 

OPERATION  OF  THE  HOLDER: 

The  holder  being  empty  and  resting  on  the  landing  blocks  at  the 
bottom  of  the  pit,  the  exhauster  forces  the  gas  through  the  inlet  pipe  until 
pressure  begins  to  accumulate  in  the  gas  between  the  holder  top  and  the 
surface  of  the  water.  The  first  effect  of  this  pressure  is  to  depress  the 
water  level  inside  the  holder,  while  it  rises  outside,  as  shown  in  the  figuree 
As  soon  as  this  pressure  is  sufficient  to  overcome  the  weight  of  the  holder, 
the  latter  begins  to  rise,  the  rollers  at  the  top  and  bottom  rolling  smoothly 
and  evenly  on  their  guide  rails.  As  more  gas  is  forced  in,  no  further  in¬ 
crease  in  pressure  occurs,  but  instead  the  holder  rises  to  make  room  for  the 
increased  volume  of  gas. 

If  at  the  same  time  the  gas  can  pass  out  of  the  holder  through  the 
outlet  pipe  “E”  the  holder  will  rise  if  the  quantity  of  gas  forced  in  is  greater 
than  that  which  passes  out,  and  the  holder  will  descend  if  the  quantity 
passing  out  through  the  outlet  pipe  is  greater  than  the  quantity  forced  in. 

If  the  gas  is  made  at  the  same  rate  throughout  the  entire  day  and  is 
forced  into  the  holder  in  a  steady  flow,  it  is  clear  that  during  the  hours 
when  a  smaller  amount  of  gas  is  being  burned  than  is  made  the  holder  will 
rise,  and  during  the  evening  hours  when  a  larger  quantity  of  gas  is  being 
burned  than  is  made  the  holder  will  fall.  In  this  way  the  gas  is  stored  in 
the  holders  during  the  hours  of  small  consumption  for  use  during  the  hours 
of  large  consumption. 

Figure  7  shows  how  the  quantity  of  gas  that  can  be  stored  may  be 
increased  without  increasing  the  size  of  the  holder  tank. 

This  is  accomplished  by  making  the  holder  in  two  or  more  sections, 
working  one  within  the  other  like  a  telescope,  and  by  increasing  the  height 
of  the  guide  columns. 

Let  us  suppose  the  holder  empty, — that  is,  all  of  the  sections  resting 
on  the  landing  blocks.  If  gas  is  now  admitted  the  inside  section  “A,”  hav¬ 
ing  a  tight  top,  begins  to  rise  from  the  landing  blocks  as  gas  is  forced  into 
the  holder.  To  the  bottom  of  this  section  a  water-tight  annular  cup  “B,” 
running  entirely  around  it,  is  fastened  as  shown.  This  cup  is  strong  enough 
to  carry  the  weight  of  the  section  “C”  next  to  it,  to  which  there  is  riveted 
at  its  top  an  inverted  cup  “D,”  the  inside  sheet  or  apron  of  which  will  reach 
over  far  enough  to  dip  into  the  water  of  the  cup  “B”  when  enough  gas  has 
been  forced  into  the  holder  to  raise  the  inner  section  “A”  to  a  level  where 
its  cup  “B”  will  engage  the  inverted  cup  “D.”  As  more  gas  is  forced  in, 
the  inner  section  will  continue  to  rise,  lifting  the  second  section  with  it 
while  the  depth  of  the  water  in  the  cup  “B”  will  prevent  an  escape  of  gas 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


19 


where  the  two  sections  unite.  All  holders  in  Philadelphia  are  built  in  this 
way,  some  having  three,  some  four  and  some  five  such  sections,  or  “lifts.” 

It  is  evident  that  after  the  first  section  has  emerged  from  the  water 
and  the  second  section  is  hooked  on,  the  weight  of  the  metal  and  the  water 
in  the  cup  of  the  first  section  will  add  to  the  weight  pressing  down  upon 
the  gas  and  thereby  increase  the  pressure  of  the  gas  within  the  holder  and 
offer  greater  resistance  to  the  inflow  of  gas  from  the  works.  Hence,  as 
each  section  is  filled  and  rises  from  the  water  there  will  be  a  step-up  in  the 
pressure  of  gas  in  the  holder.  It  is  also  evident  that  the  first  or  inner 
section  must  have  sufficient  weight  in  itself  alone  to  give  the  pressure 
required  to  force  the  gas  through  the  mains  in  sufficient  quantity  to  give 
the  best  results.  The  added  pressure,  due  to  each  section  as  hooked  on,  is 
therefore  in  excess  and  some  means  must  be  provided  to  reduce  this  pressure 
to  the  desired  amount.  This  duty  is  performed  by  the  gas  governor  which 
is  interposed  between  the  outlet  of  the  holder  and  the  inlet  of  the  distrib¬ 
uting  mains. 


The  tank  shown  in  Figure  7  differs  from  that  shown  in  Figure  6. 
Here  the  tank  is  built  of  steel  plates  riveted  together  and  set  on  a  concrete 
foundation  on  the  top  of  the  ground.  This  form  of  tank  has  been  used 
quite  commonly  in  recent  years. 


20 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


PRESSURE  GAUGE: 

Figure  8  shows  one  form  of  gauge 
by  which  the  pressure  of  gas  is  meas¬ 
ured.  It  consists  of  a  “U”  tube  made 
of  glass,  carrying  a  scale  graduated  in 
inches  and  one-tenth  inches  between  the 
two  legs  of  the  tube.  The  top  of  one 
leg  of  the  gauge  is  connected  to  the 
main  by  a  pipe.  The  other  leg  is  left 
free  or  open  to  the  air.  The  tube  is 
filled  with  water  to  reach  in  the  legs 
to  half  their  height.  When  the  cock 
“A”  is  turned  on,  the  pressure  of  the 
gas  in  the  main,  passing  up  through  the 
connecting  pipe,  will  push  the  water 
down  in  the  connected  leg  and  up  a 
corresponding  distance  in  the  free  leg 
until  the  weight  of  the  excess  column 
of  water  in  the  free  leg  will  be  balanced 
by  the  pressure  of  gas  exerted  on  top 
of  the  water  in  the  connected  leg.  The 
height  that  the  water  in  the  free  leg 
stands  above  the  height  of  the  water  in 
the  connected  leg  is  used  to  express  the 
pressure  exerted  by  the  gas.  To  illustrate,  if  the  water  in  the  connected  leg  is 
pushed  down  two  inches,  and  in  the  free  leg  up  two  inches,  there  would  be  a 
difference  of  four  inches  and  the  gas  would  be  said  to  be  exerting  a  pressure 
equal  to  four  inches  of  water.  This  (4"  of  water)  is  about  average  pressure 
of  the  gas  in  the  distributing  mains  around  the  City  of  Philadelphia. 

We  have  seen  that  the  pressure  of  the  gas  existing  in  the  holders  is 
always  somewhat  greater  than  is  required  in  the  mains  and  that  this  pres¬ 
sure  varies  according  to  the  amount  of  gas  that  is  stored  in  the  holder. 
This  pressure,  if  not  controlled,  would  cause  serious  inconvenience  to  the 
consumer.  It  would  cause  the  gas  to  issue  through  the  various  burners  at 
a  more  rapid  rate,  causing  poor  combustion,  and  no  fixed  adjustment  of 
them  could  be  made  on  account  of  the  great  variations  in  pressure  that 
would  ensue  throughout  the  entire  distributing  mains.  The  pressure  must 
be  controlled  in  such  a  way  as  to  maintain,  for  any  desired  length  of 
time,  a  certain  uniform  pressure  at  the  inlet  to  the  distributing  mains,  and 
this  pressure  must  be  changed  from  time  to  time  as  the  demands  for  gas 
vary.  This  is  the  province  of  the 

GAS  GOVERNOR: 

A  simple  form  of  governor  is  shown  in  Figure  9:  It  consists  essentially 
of  a  cast  iron  valve  box  (containing  a  double  balanced  valve)  inserted  in  the 
main  leading  from  the  outlet  of  the  holder  to  the  street  mains;  of  a  cast  iron 
water  tank  placed  vertically  over  the  valve  box  not  necessarily  directly 
upon  it,  with  a  bell  made  of  sheet  iron,  similar  to  a  small  gas  holder  work¬ 
ing  in  the  tank,  this  bell  being  fastened  to  the  valve  rod  so  that  as  it  rises  and 
falls  the  valve  rod  moves  with  it.  The  valve  rod  continues  upward  through 


FIG.  8 

Pressure  Gauge  and  Bell  and  Spigot 
Pipe  Joint 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia  21 


the  cast  iron  top  of  the  water 
tank  and  has  fastened  to  it  a 
collar  for  the  support  of  iron 
weights  which  can  be  put  on 
or  taken  off  as  desired.  Fast¬ 
ened  to  the  top  of  the  valve 
rod  is  a  chain  or  chains  leading 
to  counterweight  levers  by 
which  some  of  the  weight  of 
the  rod  and  its  appurtenances 
can  be  supported  by  the  coun¬ 
terweights  suspended  from  the 
other  arm  of  the  lever.  A 
small  pipe,  “B,”  is  screwed 
into  the  main  at  the  outlet 
of  the  governor,  passes  in 
through  the  bottom  of  the 
cast  iron  tank  and  up  through 
the  water  so  that  there  will 
always  be  gas  in  the  bell  at  the 
same  pressure  as  at  the  inlet  to 
the  street  main.  This  gas  pres¬ 
sure  in  the  bell,  together  with 
the  counterweights,  supports 
the  weight  of  the  valve  rod  and 
holds  the  valves  steady  without  opening  or  closing,  so  long  as  the  flow  of 
gas  is  constant. 

If  the  consumption  of  gas  along  the  lines  of  the  mains  increases,  the 
pressure  in  the  main  at  the  connection  to  the  pipe  “B”  will  tend  to  be 
reduced,  the  bell  will  lower,  the  valves  will  open  wider  and  a  large  volume 
of  gas  will  pass  through  into  the  main,  thereby  restoring  or  maintaining  the 
pressure.  As  the  consumption  of  gas  along  the  lines  of  the  mains  decreases 
there  will  be  a  momentary  increase  in  pressure  at  the  connecting  point  of 
the  pipe  “B,”  the  bell  will  rise  and  the  valves  will  tend  to  close,  thereby 
reducing  the  flow  of  gas  into  the  mains.  By  this  automatic  opening  and 
closing  of  the  valves  the  pressure  at  the  inlet  to  the  mains  can  be  kept 
uniform,  so  that  when  there  is  a  large  change  in  the  quantity  of  gas  con¬ 
sumed  along  the  lines  of  the  mains  the  governor  will  prevent  changes  of 
pressure  in  the  mains. 

The  case  may  arise  where  there  is  a  large  increase  in  the  consumption 
of  gas  at  some  middle  point  along  the  lines  of  the  mains,  in  which  event 
it  is  necessary  to  increase  the  usual  pressure  at  the  outlet  of  the  governor 
in  order  that  there  shall  be  no  material  loss  in  pressure  at  the  far  end  of 
the  mains.  To  accomplish  this,  the  governor  valves  being  nicely  balanced 
by  the  weight  of  the  rod  and  its  appurtenances  tending  to  open  the  valves 
and  the  pressure  of  the  gas  in  the  holder  and  the  counterweights  tending  to 
close  the  valves,  then  the  weight  of  the  valve  rod  and  its  appurtenances  is 
further  increased  and  the  extra  pressure  desired  will  be  required  under  the 
bell  of  the  holder  to  restore  the  balance.  In  this  way  the  pressure  at  the 
inlet  to  the  mains  can  be  maintained  within  such  narrow  limits  as  not  to 


F  I  G  .  9 

Simple  Form  of  Gas  Governor 


22  The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


be  detected  on  the  pressure  gauge,  and  the  attendant  can  add  weights  to 
the  valve  stem  as  required  during  periods  of  heavy  consumption  and  re¬ 
move  them  again  during  periods  of  light  consumption. 

In  the  larger  cities  where  many  hundreds  of  miles  of  mains  are  laid, 
the  decrease  in  pressure  from  the  governors  at  the  works  to  the  farther 
ends  of  the  mains  would  be  so  great  as  to  require  extremely  large,  and 
therefore  very  expensive,  mains  to  deliver  the  gas  without  great  variations 
in  pressure  between  the  times  of  small  consumption  and  large  consumption. 
This  can  be  obviated  by  locating  additional  holders  at  various  points  along 
the  lines  of  the  mains  from  which  gas  can  be  fed  into  the  mains,  thus 
maintaining  a  large  flow  of  gas  throughout  the  entire  distribution  system 
without  great  changes  in  pressure.  These  holders  are  supplied  with  gas  by 
separate  mains  connecting  them  to  pumps  at  the  works  by  which  gas  can  be 
pumped  rapidly  from  the  works  under  high  pressure  to  fill  the  holders. 

The  pipes  laid  in  the  city  streets  for  conveying  water,  gas  or  other 
commodities  are  called  “mains.” 

THE  MAINS: 

The  gas  mains  are  made  generally  of  cast  iron  in  various  diameters 
from  two  inches  up  to  sixty,  and  in  sections  of  twelve  feet  in  length.  A 
pipe  laid  in  the  ground  of  the  city  must  resist  corrosion  or  rust;  it  must  not 
leak  gas  outward,  nor  if  laid  under  water  must  it  leak  water  inward;  it 
must  be  strong  enough  to  resist  breaking  by  weight  of  the  ground  above 
or  by  movement  of  the  ground  due  to  frost  or  by  crushing  effect  of  heavy 
weights  passing  over  the  streets;  it  must  be  jointed  together  so  as  to  resist 
being  pulled  apart  or  broken  by  contraction  and  expansion  during  change 
of  seasons,  particularly  after  lying  for  months  under  a  coating  of  ice;  and 
in  going  up  and  down  hills  it  must  be  laid  so  that  what  condensation  occurs 
in  the  mains  will  flow  to  drip  pots  inserted  along  the  lines  of  the  mains  at 
the  low  points,  from  which  the  condensation  may  be  pumped  and  carried 
back  to  the  gas  works. 

The  usual  form  of  joint  is  shown  in  Figure  8  in  which  one  end  of  a 
length  of  cast  iron  pipe  terminates  in  an  enlargement  described  as  a  bell, 
and  the  other  end,  called  a  spigot,  is  straight  with  a  slight  thickening  of 
the  iron  at  the  end.  This  is  known  as  a  bell  and  spigot  joint  and  the  drawing 
of  the-  pipe  shows  the  method  of  joining  the  bell  and  spigot.  The  spigot 
end  of  one  length  of  pipe  is  introduced  into  the  bell  end  of  the  adjoining 
length,  carefully  centered  and  a  packing  of  jute  laid  in  the  form  of  rope  in 
several  sections  is  forced  into  the  bell  end  around  the  spigot  and  driven 
tightly  home,  leaving  vacant  a  space  of  several  inches  around  the  opening 
of  the  bell.  A  roll  of  damp  clay  or  other  form  of  joint  runner  is  then  laid 
around  the  bell  and  molten  lead  is  run  into  the  vacant  space  between  the 
mouth  of  the  bell  and  the  jute  packing  until  it  is  entirely  filled.  The  roll 
is  then  removed  and  the  lead  is  driven  up  tightly  with  caulking  tools  and 
hammers  by  the  main  layers.  This  joint,  which  will  permit  of  some  move¬ 
ment  without  leakage,  was  generally  used  in  the  past.  Other  forms  of 
joints  are  now  in  use  and  cement  is  largely  used  in  place  of  lead. 

The  system  of  gas  mains  is  a  very  important  factor  of  the  entire  gas 
plant  and  represents  a  large  percentage  of  the  total  investments  The  size 
of  the  mains  is  determined  both  from  investigation  and  experience,  for  it 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


is  necessary,  not  only  to  pass  the  gas  required  when  the  mains  are  laid, 
but  to  provide  for  the  additional  gas  that  will  be  used  with  the  growth  of 
the  business  in  that  locality.  Every  street  in  the  built-up  sections  of  the 
city  must  have  its  gas  main,  and  in  some  cases  a  main  on  each  side  of  the 
street  is  required.  They  are  proportioned  in  size  so  that  pressures  through¬ 
out  the  city  will  not  change  very  greatly,  and,  what  is  more  important,  so 
that  each  consumer  will  not  find  a  great  variation  in  pressure  during  the 
different  hours  of  the  day  and  night.  He  should  have  nearly  the  same 
pressure  when  a  small  amount  of  gas  is  being  used  as  he  has  when  all  his 
neighbors’  and  the  street  lamps  are  consuming  gas  from  the  mains. 

With  this  in  mind  it  is  easy  to  understand  that  rapidly  growing  cities 
outgrow  entirely  the  system  of  mains  first  put  in.  It  is  therefore  necessary 
sometimes  to  build  holders  in  sections  of  the  city  remote  from  the  gas 
works  which  can  feed  their  gas  directly  into  those  parts  of  the  mains  in 
which  low  pressures  are  likely  to  occur.  When  such  holders  are  erected  (and 
there  are  many  in  Philadelphia),  it  is  necessary  to  run  separate  lines  of 
large  mains,  which  are  entirely  disconnected  from  the  distributing  system, 
through  which  gas  can  be  pumped  from  the  works  at  high  pressures  directly 
into  these  holders.  In  other  places  an  additional  supply  of  gas  is  obtained 
in  the  main  system  by  connecting  a  separate  main  through  which  gas  can 
be  pumped  at  high  pressures  to  the  distributing  system,  and  passing  the 
gas  from  the  pumping  main  into  the  distributing  mains  through  a  governor 
where  the  pressure  can  be  reduced  and  maintained  at  the  holder 
outlet. 

If  main  laying  were  not  done  by  careful,  experienced  workmen,  it  would 
be  the  source  of  great  loss  of  money  to  the  gas  company  and  great  annoyance 
to  the  citizens  of  the  city  because  of  leaks,  unpleasant  odors  and  frequent 
digging  up  of  streets,  and  sometimes  by  frequent  renewal  of  mains  because 
of  broken  pipes.  Great  care  must  be  exercised  in  leveling  and  packing  the 
soil  underneath  the  mains  and  supporting  their  weight  and  refilling  and 
tamping  the  ground  so  that  every  portion  of  the  mains  may  rest  upon  a 
tightly  packed  and  immovable  bed  at  a  sufficient  depth  below  the  level  of 
the  street  so  as  to  be  unaffected  by  the  passage  of  unusually  heavy  loads 
over  the  roads. 

Gas,  from  the  time  it  leaves  the  works  until  it  reaches  the  burners  of 
the  consumers,  except  when  stored  in  outlying  holders,  is  not  subject  in 
continuity  of  its  supply  to  those  changes  in  atmospheric  conditions  that 
cause  trouble  to  many  of  the  other  companies  distributing  their  product 
under  city  franchises;  nor  is  the  supply  of  gas  disturbed,  as  is  frequently 
the  case  with  the  supply  of  water,  by  reason  of  broken  pipes  and  large 
connections.  When  a  water  pipe  leaks  it  is  apt  to  wash  the  foundation  from 
under  it.  The  water  pipe  is  exposed  to  heavy  pressures  due  to  the  water 
on  the  inside.  The  sudden  movement  of  large  quantities  of  water  is  apt 
to  put  unusual  strains  on  the  pipe.  From  all  such  effects  the  supply  of  gas 
is  undisturbed.  The  holders  are  strongly  built  for  their  purposes,  are  not 
affected  by  lightning,  can  be  kept  unaffected  by  snow  or  sleet  or  other  dis¬ 
turbing  causes,  and  have  stored  in  them  large  quantities  of  gas  made 
ready  for  distribution  through  the  undisturbed  mains  of  the  city,  capable 
of  supplying  the  consumers  for  many  hours  if  it  were  necessary  for  any 
reason  to  stop  the  manufacture  of  gas. 


24  The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


In  large  cities,  such  as  Philadelphia,  where  the  beds  of  the  streets  are 
occupied  by  a  number  of  mains  and  other  apparatus  of  public  service  com¬ 
panies,  a  defect  that  develops  in  one  system  may  reach  and  cause  trouble 
and  sometimes  discontinuance  of  supply  through  the  other  systems.  Elec¬ 
tricity  leaking  from  electric  mains,  conduits  or  tracks  may  affect  and  cause 
leakage  in  either  gas  or  water  mains.  Water  leaking  in  considerable  quan¬ 
tity  from  water  mains  may  wash  the  foundations  from  under  the  other 
systems.  It  is  necessary,  therefore,  to  have  in  well  regulated  companies  in 
the  larger  cities  a  large  force  of  expert  men  devoting  their  entire  time  to 
the  duty  of  maintaining  the  system  of  distributing  mains  adequate  for  the 
supply  to  all  consumers,  ready  to  repair  breaks  and  to  make  such  changes 
as  are  necessary  to  keep  the  mains  tight  and  resting  properly  in  their  beds. 
Pressures  are  observed  in  the  mains  at  all  hours  of  the  day  and  night.  Men 
called  “line  walkers,”  as  on  railroads,  travel  daily  along  the  lines  of  the 
mains  and  are  quick  to  detect  any  leaks  or  possible  causes  of  disturbances 
by  excavations  made  by  others  across  the  beds  of  the  mains. 

SERVICE  PIPES: 

In  front  of  each  house  a  hole  is  drilled  in  the  top  of  the  main  and  a 
pipe  large  enough  to  provide  gas  for  all  probable  needs  is  led  into  the 
premises  under  the  sidewalk.  This  pipe  is  called  a  “service.”  It  is  gener¬ 
ally  of  wrought  iron  or  steel  with  screwed  connections,  and  to  its  end  in 
the  cellar  of  the  premises  a  meter  for  measuring  the  gas  used  in  the  premises 
is  connected. 

METER: 

If  a  storekeeper  wished  to  draw  out  of  a  barrel  a  liquid  such  as  molasses* 
cider  or  oil  and  to  know  exactly  the  quantity  he  drew  out,  he  would  fill 
a  measure  holding  one  quart  or  one  gallon  a  number  of  times,  and  he  would 
keep  a  record  of  that  number.  If  he  measured  the  quantity  exactly  he  must 
have  observed  four  things  in  the  process: 

First:  That  he  filled  the  measure  each  time  to  the  line  which 

marked  exactly  one  quart  or  one  gallon. 

Second:  That  he  completely  shut  off  the  supply. 

Third:  That  he  completely  emptied  the  measure  before  opening 

the  supply  again. 

Fourth:  That  he  kept  an  accurate  account  of  the  number  of 
measures  so  filled  and  emptied. 

This  is  a  true  method  of  measuring  liquids,  but  it  is  clear  that  one 
additional  step  must  be  taken  in  the  measure  of  the  gas  supplied  to  the 
consumers,  because  in  the  latter  case  the  supply  can  not  be  interrupted 
during  the  period  of  emptying  the  measure.  The  dry  gas  meter  in  a  similar 
way  measures  the  volume  of  gas  delivered  through  it,  but  instead  of  one 
measure  being  alternately  filled  and  emptied,  in  the  meter  there  are  four 
of  these  measures  in  operation  continuously,  one  or  more  filling  while  there 
is  always  at  least  one  emptying.  This  insures  a  continuous  delivery  of  gas. 

These  four  measures  do  not  have  to  be  of  exactly  the  same  size,  but 
each  of  them  must  be  filled  in  the  same  way  every  time  so  that  each  com- 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia  25 


plete  round  of  filling  and  emptying  of  the  four  measures  shall  measure 
exactly  the  same  quantity  of  gas.  Instead  of  keeping  tally  of  the  number 
of  times  that  each  is  filled,  as  in  the  case  of  the  grocer,  it  is  necessary 
in  the  meter  that  the  amount  of  gas  passed  shall  be  automatically  registered 
and  this  is  done  on  the  meter  dial. 

Figure  10  shows  the  case  and  the  four  compartments. 

Figure  11  shows  the  mechanism  operating  in  these  compartments. 

Fig.  10  Fig.  11 


Dry  Gas  Meter  (Case)  Mechanism  for  Operating  Dry  Gas  Meter 


The  two  lower  compartments  are  the  measuring  compartments  and 
the  two  upper  compartments  contain  the  valves  and  the  system  of  levers, 
shafts  and  gears  necessary  for  filling  and  discharging  the  measuring  com¬ 
partments  and  for  registering  on  the  dial  the  amount  of  gas  that  has  passed 
through  the  compartments. 

In  each  of  the  lower  compartments  a  thin  metal  disc  is  connected  to 
the  central  partition  by  means  of  a  band  of  soft,  collapsible,  oiled  and  gas- 
tight  leather.  The  metal  disc  is  kept  vertical  in  its  movements  by  means 
of  wire  guides  and  by  the  wide  “flag”  lever,  by  which  its  movement  is  con¬ 
veyed  to  the  vertical  rod  which  extends  into  the  upper  compartment  and 
operates  the  valves. 

Gas  is  alternately  and  automatically  admitted  and  expelled,  first  from 
the  compartment  inside  the  bellows  and,  second,  from  the  one  outside  of 
the  bellows.  _  The  operating  force,  it  will  be  understood,  is  the  difference 
between  the  pressure  in  the  mains  due  to  the  pressure  from  the  holder,  and 
the  pressure  on  the  outlet  of  the  meter,  due  to  opening  of  a  burner  cock. 


26  The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


As  gas  is  admitted  to  the  compartment  inside  the  bellows,  the  bellows  open 
out  and  the  metal  disc  is  forced  toward  the  front  of  the  meter,  the  move¬ 
ment  is  communicated  to  the  vertical  shaft,  which  in  turn  operates  the 
valves  in  the  upper  compartment  and  also  the  gears  connecting  with  the 
dial  on  the  front  of  the  meter.  While  the  compartment  is  filling  with  fresh 
gas  from  the  inlet  duct  of  the  meter,  the  compartment  outside  of  the  bellows 
is  emptying  into  the  outlet  duct  of  the  meter.  The  vertical  shafts  in  each 
of  the  lower  compartments  combine  through  levers  to  operate  the  two  valves. 

Figure  12  shows  one  position  in 
the  movement  of  the  measuring  com¬ 
partments  and  the  valves  of  the 
meter.  Here  the  gas  is  just  finish¬ 
ing  (being  discharged  from  the  inner 
compartment  of  the  left  hand  bel¬ 
lows,  and  the  outer  compartment  is 
completely  filled  with  gas.  The 
inner  compartment  of  the  bellows  on 
this  side  is  entirely  empty  and  the 
exterior  compartment  of  the  bellows 
is  entirely  closed  and  there  is  no 
communication  with  the  inlet  or 
outlet  of  gas  to  either  compartment. 
In  other  words,  one  measure  is  en¬ 
tirely  empty  and  the  other  is  entirely 
filled.  The  supply  from  the  grocer’s 
barrel  is  closed  off  from  these  meas¬ 
ures. 

On  the  right  hand  side  the  in¬ 
terior  of  the  bellows  is  filling  and 
the  exterior  is  discharging.  While 
the  interior  is  filling  there  is  no 
opportunity  for  the  gas  to  be  dis¬ 
charged  from  this  measure  or  compartment,  and  there  is  no  opportunity 
for  fresh  gas  to  enter  the  compartment  that  is  being  discharged. 

The  motion  of  the  disc  on  the  right  hand  side  is  being  conveyed  by 
means  of  the  “flag”  arm  to  the  vertical  shaft,  which  is  so  connected  as  to 
operate  the  valve  “V”  for  admission  and  discharge  of  gas  to  the  left  hand 
compartment.  The  valve  is  about  to  move  so  that  the  port  “Q”  will  connect 
with  the  discharge  port  “O”  and  the  port  “P”  will  be  opened  to  the  flow 
of  fresh  unmeasured  gas  into  the  interior  of  the  bellows  “D.” 

Meanwhile  on  the  right  hand  side  the  gas  in  the  outer  compartment  is 
passing  out  through  the  port  “q”  into  the  discharge  port  “o,”  while  the 
port  “p”  is  now  entirely  open  to  admit  gas  to  the  interior  of  the  bellows 
“d,”  which  is  about  half  filled.  The  valve  “v”  is  about  to  begin  to  close 
the  port  “q”  from  measured  gas  and  the  port  “p”  from  fresh  gas,  but  gas 
will  continue  to  flow  through  these  ports  until  the  valve  has  moved  far 
enough  to  entirely  cover  them  or  until  the  inside  of  the  bellows  “d”  has 
been  completely  filled,  by  which  the  time  valve  “V”  on  the  left  will  have 
moved  so  that  the  port  “P”  will  be  fully  opened  for  admission  of  gas  to 
the  bellows  “D,”  which  will  then  be  half  filled  or  in  the  same  condition 


Fig.  12 


Dry  Gas  Meter 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia  27 


as  shown  in  the  compartment  “d”  in  the  figure,  and  the  port  “Q”  will  be 
wide  open  for  the  discharge  of  gas  from  the  outer  compartment  into  the 
outlet  “O.” 

It  is  absolutely  essential  for  the  accurate  measurement  of  gas  by  this 
method  that  the  bellows  shall  contract  and  expand  to  exactly  the  same  extent 
for  each  emptying  and  filling.  The  meter  dial  registers  the  number  of 
times  that  these  compartments  are  filled  and  emptied,  and  it  expresses  that 
record  in  terms  of  cubic  feet  of  gas  passed. 

METER  PROVER: 

Each  meter  after  construction  is  tested  for  leakage,  for  ease  of  working 
parts,  and  finally  is  connected  to  an  instrument  called  a  “meter  prover”  for 
adjusting  the  operation  of  its  valves,  so  that  the  passage  of  a  trial  number 
of  cubic  feet  as  exactly  measured  by  the  prover  shall  agree  with  the  regis¬ 
tration  shown  on  the  meter  dial. 

The  meter  prover  consists  of  a  very  accurately  constructed  small  holder 
having  a  capacity  of  about  five  cubic  feet,  moving  up  and  down  in  a  tank 
of  water  and  provided  with  a  scale  showing  accurately  the  changes  in 
capacity  for  changes  in  lineal  height. 

These  provers  are  the  working  “capacity  standards”  by  which  the 
accuracy  of  large  numbers  of  meters  is  tested.  They  have  the  merit  of  quick 
operation  within  the  limits  of  accuracy  necessary. 

The  calibration  of  these  provers  as  to  their  accuracy  before  use  is, 
however,  a  longer  process,  requiring  exact  control  of  the  equal  temperature 
of  room,  containers,  water  and  measuring  fluid  (either  air  or  gas).  The 
calibration  is  effected  by  a  Cubic  Foot  Bottle,  bulbous  in  shape  and  made  of 
copper.  This  bulb  draws  down  to  narrow  glass  tubes  connected  at  top  and 

bottom,  upon  which  are  scribed  two  fine  lines.  At  a  fixed  temperature  and 

pressure  the  contained  volume  of  the  bottle  between  these  two  lines  is 
exactly  one  cubic  foot. 

Air  is  measured  first  by  the  bottle,  one  cubic  foot  at  a  time,  and  then 
displaced  by  water  and  forced  into  the  prover.  In  this  way  the  vertical 

scale  on  the  prover  is  calibrated  in  integral  cubic  feet,  after  which  the 

subdivision  into  one-tenth  cubic  feet  is  effected  by  equal  parts. 

The  bottle  itself  has  its  volume  determined  with  the  most  extreme 
care  by  the  Bureau  of  Standards  at  Washington  which  certifies  its  accuracy. 

In  the  meter  just  described  the  amount  of  gas  is  observed  at  regular 
intervals  by  reading  the  dials  and  a  bill  is  presented  to  the  consumer  for 
the  amount  of  gas  consumed  since  the  previous  reading;  that  is  to  say,  from 
the  total  amount  of  gas  that  has  passed  the  meter,  as  shown  on  the  dial  at 
the  time  of  the  reading,  the  total  amount  of  gas  that  had  passed  through 
the  meter,  as  shown  on  the  dial  at  the  time  of  previous  reading,  is  subtracted 
and  the  difference  is  charged  to  the  consumer  at  the  rate  fixed  per  thousand 
cubic  feet. 

HOW  TO  READ: 

The  method  of  reading  a  meter  is  shown  on  each  gas  bill  presented, 
as  illustrated  in  Figure  13.  By  means  of  the  instruction  there  given  each 
consumer  may,  at  any  time,  determine  the  rate  at  which  he  is  using  gas. 

Another  form  of  meter,  known  as  “prepayment  meter,”  is  one  in  which 


28 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


a  coin  placed  in  a  slot  of  the  meter  will  permit  by  mechanical  arrangement, 
a  fixed  amount  of  gas,  equal  in  quantity  to  the  amount  that  the  coin  would 
purchase,  to  flow  through  the  meter,  when  the  meter  automatically  locks 
and  no  more  gas  will  pass  until  another  coin  is  put  into  the  slot. 


Fig.  13 


Each  division  on  the  right  hand  circle  denotes  100  feet,  and  on  the  oentre 
circle,  1,000  feet,  and  on  the  left  hand  circle,  10,000  feet.  To  take  a  state¬ 
ment  from  the  meter,  begin  at  the  left  and  set  down  the  lowest  figures  next 
to  the  hands  on  each  circle,  which  in  the  diagram  are  8,  2  and  8;  showing 
the  statement  to  be  32,300.  If  at  a  former  observation  the  hands  were  at  the 
dotted  lines,  the  statement  then  was  20,200;  and  the  difference  between  the 
two  statements  is  the  amount  of  gas  consumed— viz.,  12,100  cubic  feet. 

Explanation  of  Gas  Meter  Dial 

The  outlet  of  a  meter  is  connected  to  the  house  piping,  which  generally 
consists  of  one  or  more  pipes  rising  from  the  main  pipe  in  the  cellar  to  the 
different  floors,  according  to  the  size  of  the  house,  lateral  pipes  being  run 
between  the  joists  of  the  ceiling  or  along  the  side  walls  and  coming  through 
the  plastering  at  certain  places,  to  which  the  fixtures  are  attached.  Another 
line  of  pipe  will  probably  be  run  to  supply  other  appliances  used  for  burn¬ 
ing  gas  besides  lighting,  such  as  gas  cooking  stoves,  water  heaters  and  in 
industrial  establishments  for  the  large  number  of  appliances  in  which  gas 
is  used. 

Before  gas  is  supplied  to  a  house,  application  must  be  made  at  the  gas 
office  to  have  a  meter  connected  and  the  gas  turned  on.  The  house  piping 
is  first  put  under  pressure  by  the  company’s  inspector  by  means  of  an  air 
pump,  all  other  cocks  except  to  the  pump  being  closed  and  a  U  gauge  being 
placed  in  the  line  to  indicate  the  pressure.  If  the  piping  is  tight  the  pres¬ 
sure  as  shown  by  the  gauge  should  remain  at  the  height  indicated  when 
the  pump  cock  is  also  closed.  If,  however,  the  piping  leaks,  the  falling 
column  in  the  gauge  indicates  it,  and  such  leak  must  be  found  and  stopped 
before  gas  will  be  turned  on. 

METHODS  OF  USING  GAS: 

The  term  “burning,”  as  applied  to  gas,  means  the  union  of  its  carbon 
and  hydrogen  with  oxygen  obtained  from  the  air, — air  containing  about 
four  parts  nitrogen  and  one  of  oxygen.  This,  called  oxygenation  or  oxida¬ 
tion,  is  a  chemical  union  giving  off  heat  which  is  a  form  of  energy,  and  it 
is  this  heat  that  is  used  to  produce  the  results  obtained  in  many  different 
methods  of  using  gas.  These  methods  of  burning  may  be  divided  into  four 
classes: 

First:  That  in  which  gas  and  air  (O  +  N4)  do  not  mix  prior 

to  the  point  of  ignition. 

Second:  That  in  which  gas  and  part  air  (O  +  N4)  do  mix  prior 
to  the  point  of  ignition. 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia  29 


Third:  That  in  which  gas  and  total  air  (0  +  N4)  do  mix  prior 

to  the  point  of  ignition. 

Fourth:  That  in  which  gas  and  O  (only)  do  not  mix  prior  to  the 
point  of  ignition. 

First:  If  a  thin,  flat  stream  of  illuminating 

gas  is  allowed  to  issue  from  a  burner, 
such  as  a  lava  tip  (Figure  14),  it 
will,  when  ignited,  burn  with  a 
bright,  luminous  flame.  The  oxygen 
of  the  air  in  contact  with  the  surface 
of  the  stream  of  gas  can  only  com¬ 
bine  with  the  carbon  and  hydrogen 
of  the  gas  when  they  have  been 
raised  to  a  certain  high  tempera¬ 
ture;  they  will  not  combine  when 
cold.  This  temperature  is  momen¬ 
tarily  applied  with  a  lighted  match, 
or  an  electric  spark,  or  a  small 
burning  jet  of  gas  called  a  pilot  light.  But  as  soon  as  oxi¬ 
dation  begins,  the  heat  evolved  from  the  chemical  union 
is  more  than  sufficient  to  maintain  the  temperature  neces¬ 
sary  for  continued  oxidation  of  the  gas  flowing  from  the 
burner. 

The  gas  is  now  burning  only  on  the  very  thin  outer 
surface  of  its  stream  where  the  air  can  touch  it  and  the 
temperature  of  this  surface  is  very  high — over  3000° 
Fahrenheit.  This,  in  turn,  heats  the  unburned  gas  inside 
the  surface  to  almost  the  same  temperature. 

All  substances  simple  and  complex,  including  this  il¬ 
luminating  gas,  exist  in  the  unit  form  of  molecules  which 
may  be  considered  as  restraining  envelopes.  Within  these 
tiny  envelopes  in  a  high  state  of  activity  are  the  atoms, 
the  various  ways  in  which  they  pair  off  or  combine  giving 
the  peculiar  character  to  their  enveloping  molecule,  by 
which  in  turn  each  substance  is  distinguishable  from  all 
other  substances. 

The  activity  of  these  atoms  is  increased  by  raising 
their  temperature,  and  for  each  kind  of  molecule  there  is 
a  temperature  at  which  it  disrupts  and  no  longer  can  con¬ 
fine  its  captive  atoms. 

It  is,  then,  a  chemical  fact  that  the  molecules  of  the 
gas,  made  up  of  the  union  of  atoms  of  carbon  and  hydrogen, 
cannot  hold  together  at  the  above  temperature  and  in  con¬ 
sequence  the  hydrogen  is  liberated  as  a  gas  and  the  carbon 
turns  into  finely  divided  particles,  and  if  cooled  at  this 
stage  by  putting  a  cold  substance,  such  as  a  nail,  into  the 
interior  of  the  flame,  the  nail  would  soon  be  covered  with 
these  fine  particles  of  carbon,  like  lamp-black.  It  is  these 
fine  particles  of  carbon  released  inside  the  stream  of  gas 
beyond  the  reach  of  oxygen,  and  being  heated  by  the  com- 


Fig.  14 


Lava  Tip  Gas  Burner 


30  The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


bustion  on  the  surface,  that  become  incandescent  and  give 
the  luminous  effect  to  the  flame.  Thus  an  incandescent 
carbon  light  is  as  truly  formed  as  by  the  electric  method 
in  which  the  carbon  in  a  filament  is  heated  by  electric  cur¬ 
rent  and  the  oxygen  kept  away  by  a  wall  of  glass  instead 
of  by  a  wall  of  incombustible  gas.  As  soon  as  these  free 
atoms  of  hot  hydrogen  and  carbon  reach  the  surface,  how¬ 
ever,  where  oxygen  may  be  had,  they  are  instantly  con¬ 
verted  into  water  vapor  and  carbonic  acid  and  disappear 
as  products  of  combustion. 

The  number  of  carbon  particles  thus  existing  in  the 
flame  and  the  temperature  to  which  they  are  heated  deter¬ 
mine  the  amount  of  light  the  flame  produces.  For  nearly 
seventy  years  after  so-called  illuminating  gas  was  first  in¬ 
troduced  it  was  used  almost  exclusively  for  lighting  by 
means  of  burning  it  in  jets  as  just  described;  and  the  value 
of  the  gas  depended  entirely  on  the  amount  of  light  that 
was  produced  by  the  burning  of  a  certain  quantity  of  gas 
in  a  certain  time,  five  cubic  feet  per  hour  being  selected. 
The  amount  of  light  so  produced  is  expressed  in  terms  of 
the  light  of  a  certain  kind  of  candle  made  of  sperm  and 
burning  120  grains  per  hour, — the  kind  of  sperm,  the  kind 
of  wick  and  method  of  burning  being  all  very  minutely  de¬ 
scribed  by  a  committee  representing  the  House  of  Parlia¬ 
ment  of  England.  It  is  called  the  British  Standard  Candle. 

The  instrument  by  which  the  intensity  of  light  pro¬ 
duced  by  any  light  source  is  measured  is  called,  as  the  name 
implies,  a  photometer.  A  description  of  this  instrument 
will  be  found  in  the  appendix. 

The  use  of  luminous  jets  of  gas  is  not  confined  to  pur¬ 
poses  of  illumination.  Many  heating  stoves  use  this  method 
because  of  the  radiating  effect  of  the  heat  from  the  par¬ 
ticles  of  incandescent  carbon.  With  proper  reflectors  ad¬ 
vantage  can  be  taken  of  this  to  give  a  widely  diffused  heat. 

Second:  The  luminous  flame  from  a  jet  as  just  described  is  unsuited 
for  a  number  of  uses  of  gas  because  of  several  reasons: — 
its  tendency  to  deposit  unburned  carbon  whenever  the  flame 
comes  in  contact  with  a  cooler  surface,  and  also  because  a 
considerable  portion  of  the  heat  evolved  in  the  form  of 
radiant  heat  is  not  best  suited  for  application  to  the  pur¬ 
poses  required. 

Therefore,  the  principle  of  what  is  known  as  the  Bun¬ 
sen  burner  is  put  into  use  for  the  greater  number  of  devices 
in  which  gas  is  used,  such  as  water  heaters  (Figure  15), 
some  forms  of  gas  heating  stoves,  most  forms  of  gas  ccoking 
stoves  and  in  the  Welsbach  or  incandescent  mantle  lamps. 
By  this  means  the  gas  is  mixed  on  its  passage  to  the  burner, 
and  before  its  ignition,  with  about  three  times  its  quantity 
of  air.  This  is  called  primary  air.  This  has  the  effect  of 
presenting  the  mixture  at  the  opening  of  the  burner  in  such 


Water  Heater,  Showing  Proper  Combustion  of  Gas  by  Use  of  Bunsen  Burner 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


31 


form  that  the  carbon  is  partially  oxidized  to  carbon  monox¬ 
ide  and  does  not  appear  in  a  finely  divided  state,  but  on 
the  other  hand,  when  the  remainder  of  the  necessary  air 
(called  secondary  air)  is  supplied,  burns  to  a  short  blue 
flame  which  has  the  advantage  of  allowing  great  concentra¬ 
tion  of  heat  to  any  point  desired  and  which  will  not  deposit 
carbon  on  any  cold  surface,  but  which  will,  if  a  cold  sur¬ 
face  can  be  continued  in  the  flame,  cause  some  of  the  gas  to 
pass  off  unconsumed. 

The  method  of  introducing  the  gas  and  mixing  it  with 
the  proper  proportion  of  air  for  its  complete  combustion 
is  illustrated  in  Figures  16  and  17 : 


Fig.  16 


Details  of  Mixer,  Bunsen  Principle 
Fig.  17 


Same  Type  of  Mixer,  Adapted  to  Use  on  Gas  Cooking  Stoves 

Figure  16  shows  the  construction  of  one  type  of  air 
mixer.  It  is  in  the  form  of  a  bulb  in  which  the  casting  is 
solid  across  the  lower  half  of  the  front  but  open  at  the  upper 
half.  A  steel  disc  clamped  around  the  fluted  groove  of  the 
casting,  but  loose  enough  to  be  moved  by  loosening  the  set 
screw,  has  openings  cut  in  it  through  which  the  air  is  ad¬ 
mitted  to  the  mixer.  The  gas  inlet  is  in  the  center  of  this 
disc  and  the  disc  can  be  turned  around  the  gas  inlet  in  such 
a  way  as  to  change  the  size  of  the  opening  for  the  admis¬ 
sion  of  air.  The  stem  of  the  gas  inlet  orifice  is  pushed 
into  the  mixer  so  that  the  gas,  entering  under  pressure, 
induces  or  pulls  in  a  flow  of  air  through  the  openings,  and 
the  air  and  gas  are  usually  mixed  in  the  proportion  of  about 
three  volumes  of  air  to  one  of  gas  in  their  passage  to  the  burner. 

Figure  17  shows  the  same  type  of  mixer  adapted  to 
use  on  gas  cooking  stoves.  On  one  end  is  the  mixer  and 
at  the  other  the  star-shaped  burner  from  the  small  holes 


32  The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


of  which  the  mixed  gas  and  air  burn  in  jets  about  three- 
quarters  of  an  inch  long  in  a  blue  flame  (as  shown  in  Fig¬ 
ure  15).  The  closing  of  the  cock  through  which  the  gas 
is  supplied  will  reduce  the  pressure  and,  therefore,  reduce 
the  amount  of  air  that  is  drawn  in,  so  that  the  mixture 
will  be  maintained  in  about  the  proper  proportions.  If 
more  than  this  proper  amount  of  air  is  admitted  there  will 
be  a  small  explosion  and  the  gas  will  be  ignited  in  the  air 
mixer,  which  is  undesirable  since  it  heats  up  this  portion 
of  the  apparatus  rather  than  the  utensil  placed  for  use. 
If  not  enough  air  is  admitted,  luminous  tips  will  begin  to 
show  on  the  edge  of  the  small  jets  and  the  bottoms  of  uten¬ 
sils  will  be  blackened.  It  is,  therefore,  necessary  that  the 
gas  companies  from  their  experience  should  set  the  air 
mixer  so  as  to  give  the  proper  quantity  of  air,  and  this 
should  not  then  be  moved  except  by  some  experienced  person. 

In  the  Welsbach  burner  another  well-known  form  of 
mixer  is  used,  but  the  principle  upon  which  it  operates  is 
the  same. 


The  Welsbach  Tamp 


Fig.  18 


Upright  Mantle 


The  Welsbach  mantle  lamp  has  superseded  the  use  of 
the  lava  tip  to  such  a  very  large  extent  that  in  practice 
the  value  of  a  gas  may  be  said  to  depend  at  the  present 
day,  not  upon  the  amount  of  light  that  will  be  obtained 
without  previous  mixture  with  air,  but  almost  bnjjyfely  upon 
its  heating  value,  since  it  is  the  heating  value  that  becohles 
effective  in  producing  light  in  the  Welsbach  lamp.  In  the 
Welsbach  lamp  the  gas  is  also  mixed  with  two  and  a  half 
to  three  and  a  half  times  its  quantity  of  air  before  reaching 
the  burner,  and  the  burner  is  so  designed  that  the  shape 
of  the  flame  will  coincide  with  the  shape  of  the  mantle,  so 
that  the  mantle  will  lie  exactly  in  the  area  of  highest  tem¬ 
perature  of  combustion. 

It  was  the  discovery  of  Auer  von  Welsbach  that  the 
oxides  of  the  rare  elements  of  thorium  and  cerium  when 
mixed  together  in  a  correct  proportion  and  made  up  into 
the  form  of  mantles  gave  a  surface  of  exceptional  brilliancy 
when  heated  in  the  Bunsen  flame. 

There  are  various  types  of  Welsbach  lamps,  suited  to 
the  needs  of  places  which  are  to  be  lighted.  In  general 
these  are  named  in  accordance  with  the  direction  which  the 
mixture  of  gas  and  air  travels.  If  it  travels  (1)  upward  it 
is  called  an  upright  lamp;  if  (2)  downward,  an  inverted 
lamp;  some  mixing  tubes  for  use  with  clusters  of  mantles 
are  (3)  horizontal  discharging  downward,  the  attached  man¬ 
tles  being  of  the  inverted  type;  and  finally  (4),  the  newest 


33 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


type  of  lamp  devised  to  replace  the  open-flame  burner  has 
an  upright  Bunsen  tube  with  inverted  mantles. 

Like  other  gases,  when  illuminating  gas  is  heated  it 
occupies  a  larger  volume  without  increase  in  weight.  This 
adds  buoyancy  to  that  which  it  already  has  as  it  is  lighter 
than  air,  and  it  tends  more  strongly  to  rise.  For  this  rea¬ 
son  it  can  be  seen  that  the  behavior  of  the  mixtures  in  a 
hot  upright  Bunsen  tube  and  in  a  hot  inverted  Bunsen  tube 
will  be  different,  and  therefore  the  construction  will,  be 
somewhat  different  as  well  as  the  manner  of  placing  the 
mantle.  In  general,  if  the  point  of  combustion  is  higher 
than  the  point  of  admitting  primary  air,  the  hot  mixture 
is  aided  in  its  upward  flow  toward  the  mantle.  If  the  point 
of  combustion  is  lower  than  the  point  where  primary  air 
enters,  the  hot  mixture  is  somewhat  hindered  in  its  down¬ 
ward  flow  to  the  mantle.  One  effect  of  this  is  to  make  the 
flame  shapes  different,  and  hence  also  the  mantle  shapes 
which  must  conform  to  the  flames. 

The  upright  mantle  (Figure  18)  is  long,  cylindrical 
with  a  vent  hole  at  its  top,  and  rather  close  fitting  around 
the  burner;  its  maximum  light  is  given  off,  therefore,  in 
a  horizontal  direction. 


Fig.  19 


Inverted  Mantle 


The  inverted  mantle  (Figure  19)  is  shorter,  larger  in 
diameter,  hung  with  an  annular  opening  around  the  burner, 
and  is  dome  shaped  so  that  its  maximum  light  is  given 
downward  at  an  angle  where  it  is  most  desired.  This  ac¬ 
counts  for  the  popularity  in  the  past  of  the  inverted  lamp. 

Both  types  of  mantles,  it  will  be  noted,  are  suspended 
from  above,  as  mantles  are  quite  soft  and  flexible  when  in¬ 
candescent,  and  would  not  then  support  their  own  wreight 
if  stood  upright. 

All  types  of  mantle  lamps  may  now  be  had  with  pilot¬ 
lighting  attachments  for  convenience  of  ignition.  This  is 
accomplished  by  leading  gas  through  a  small  metal  tube  to 
a  position  where  it  discharges  upon  or  close  to  the  mantle 
and  then  arranging  the  valve  control  to  the  lamp  that  when 
the  main  supply  is  turned  off  the  pilot  supply  is  on,  and 


34  The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


vice  versa.  The  extinguishing  mantle  then  lights  the  on¬ 
going  pilot,  or  the  pilot  lights  the  mantle,  depending  on 
which  way  the  valve  is  turned.  Such  an  arrangement  is 
known  as  a  “by-pass  valve”  (Figure  18). 

It  is  apparent  that  after  a  lamp  has  been  turned  off 
for  some  time  its  Bunsen  tube  will  be  filled  with  air. 
Hence,  when  gas  is  again  turned  on  there  must  come  a 
moment  when  the  entering  gas  and  the  loitering  air  form 
an  explosive  mixture,  and  the  flame  would  tend  to  flash 
back  to  the  orifice  whence  the  gas  issues  near  the  primary 
air  ports.  Such  a  flash-back  will  occur  unless  the  entire 
plug  of  mixture  in  the  burner  tube  is  moving  faster  than 
the  velocity  with  which  the  explosive  wave  travels  back, 
or  else,  a  gauze  like  that  used  in  an  Humphrey  Davy  lamp 
must  be  inserted  which  will  so  lower  the  temperature  that 
the  flame  cannot  ignite  back  through  it.  Usually  gauzes 
are  placed,  and  the  remedy  is  simple  and  effective  with 
upright  burners. 


Fig.  20 


Details  of  Inverted  Mantle  Light 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


35 


The  case  is  not  so  simple  with  inverted  burners,  how¬ 
ever,  because  as  before  stated  they  already  have  a  hindrance 
to  their  downward  flow  of  hot  mixture,  particularly  at  low 
gas  pressures,  and  an  added  stoppage  would  make  the  lamp 
inefficient.  To  meet  the  need  at  this  point  a  thermostat 
was  devised,  as  shown  in  Figure  20,  which  acts  as  a  sort 
of  gauze  at  the  time  of  ignition,  but  as  the  lamp  gets  heated, 
rapidly  opens  to  permit  the  full  flow  of  air  for  a  correct 
mixture. 

Figure  21  shows  a  larger  type  of  inverted  lamp,  used 
in  industrial  and  commercial  lighting.  This  lamp  has  a 
metal  stack  which  serves  to  increase  the  draught  by  which 
secondary  air  is  supplied  to  the  outside  of  the  mantle. 


Fig.  21 


Still  larger  inverted  lamps  called  arc  lamps  are  in  use, 
in  which  two,  three,  four  or  five  inverted  mantles  are  clus- 


36  The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


tered  inside  one  globe,  and  the  stack  still  further  elongated 
for  increased  secondary  draught. 

Figure  22  shows  the  newest  type  of  lamp 
with  upright  Bunsen  tube,  yet  fitted  with  in¬ 
verted  mantles.  The  peculiarities  of  this  lamp 
are:  (a)  Its  ability  to  replace,  without  further 
equipment,  an  open-flame  burner;  (b)  its  high 
efficiency  in  entraining  over  four  volumes  of 
primary  air,  due  to  design  of  its  inside  Bunsen 
curvature;  (c)  that  the  mantles  screw  on  instead 
of  hang;  (d)  that  the  entire  mantle  head  is 
removable  and  interchangeable  like  electric 
bulbs.  It  is  thus  seen  that  many  sizes  of  low- 
pressure  gas  mantle  lamps  are  available.  In 
general,  these  lamps  yield  about  twenty  candle 
power  for  each  cubic  foot  of  gas  consumed. 

There  is  a  sufficient  variety  of  sizes  to  meet  every  need 
from  a  small  home  table  reading  lamp  to  a  lofty-mounted 
high-candle-power  factory  lamp.  And  it  is  well  to  remem¬ 
ber  that  under  artificial  illumination  where  much  of  our 
work  and  recreation  are  taken,  good  lighting  should  be 
insisted  upon, — for  health  and  nervous  tone  are  strongly 
influenced  by  the  way  we  use  our  eyes.  Illumination  should 
be  adequate,  of  good  color,  steady,  and  either  properly  dif¬ 
fused  or  directed. 

If  any  means  can  be  used  to  increase  the  temperature 
of  the  Bunsen  flame  and  hence  of  the  mantle,  then  the 
light  given  by  the  mantle  increases  at  a  far  greater  ratio 
than  that  of  the  temperature.  Any  method  by  which  an 
increased  quantity  of  gas  can  be  burned  within  the  same 
flame  volume  must  result  in  a  greater  release  of  heat  and 
hence  an  increased  temperature.  One  way  of  accomplishing 
this  is  when,  of  the  total  air  required  for  complete  combus¬ 
tion,  an  increased  percentage  of  it  is  pre-mixed  as  primary 
air. 

In  every  mixing  of  gases  for  combustion,  a  certain  time 
is  required  for  such  a  diffusion  of  molecules  throughout 
the  mass  as  will  enable  the  imprisoned  atoms  upon  their 
release  to  effect  quickly  their  new  chemical  union.  It  is 
this  time  which  is  saved  to  combustion  by  the  pre-mixing 
of  air,  and  it  is  this  increased  speed  of  releasing  and  util¬ 
izing  energy  which  raises  the  temperature. 

Three  means  may  be  named  by  which  this  increase  in 
the  primary  air  ratio  may  be  gained,  but  they  require  the 
use  of  some  power  other  than  entrainment  by  low-pressure 
gas: 

1.  The  gas  pressure  must  be  mechanically  in¬ 
creased,  by  which  a  greater  proportion  of  air 
entrainment  results. 


Fig.  22 


Upright  Bunsen  Burner  with 
Inverted  Mantles 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia  37 


2.  Air  pressure  must  be  mechanically  supplied,  by 

which  any  proportion  desired  may  be  had. 

3.  Air  and  gas  must  be  mechanically  mixed  and 

delivered  to  the  burner. 

1.  The  first  means  is  much  used  in  many  industrial 
plants  where  gas  is  burned  under  as  high  as  eight  pounds 
per  square  inch  in  order  to  get  highly  concentrated  heat 
covering  a  considerable  surface.  It  is  also  found  that 
mantle  lamps  designed  to  use  gas  under  two  to  three  pounds 
pressure  give  from  two  to  three  times  the  amount  of  light 
per  cubic  foot  of  gas  as  is  obtained  under  the  usual  main 
pressure  of  about  two  ounces. 

In  the  case  of  Welsbach  street  lighting,  where  high- 
pressure  gas  is  used,  a  separate  main  carrying  gas  at  high 
pressure  to  the  lamps  must  be  provided.  When  this  is  done 
it  is  possible  to  light  and  extinguish  all  of  the  street  lamps 
from  a  central  point,  the  same  as  the  arc  electric  lights  are 
lighted  and  extinguished.  In  Philadelphia  a  sample  of 
such  high-pressue  gas  lighting  can  be  observed  in  the 
posts  in  front  of  the  offices  of  the  gas  company  at  Broad 
and  Arch  Streets. 

2.  This  system  using  air  compressed  by  water  or  other 
power  is  correct  in  principle,  but  makes  uniformity  of  re¬ 
sults  dependent  on  two  power  sources  instead  of  one. 

3.  The  pre-mixing  of  gas  and  air  by  means  of  a 
mechanical  mixer,  and  the  delivery  of  this  mixture  to  burn¬ 
ers  safeguarded  from  flash-back  by  approved  devices  is  one 
of  the  latest  methods  of  utilizing  gas  and  is  gaining  in 
popularity.  It  can  be  seen  that  this  means  may  theoretic¬ 
ally  be  pushed  to  the  point  of  supplying  all  of  the  air  needed 
for  complete  combustion,  which  would,  for  a  number  of 
appliances,  accomplish  what  is  automatically  done  for  itself 
in  the  case  of  the  gas  engine,  as  described  in  the  next 
method. 

Third:  Coal  gas  and  water  gas  require  for  their  complete  combus¬ 

tion  from  eight  to  twelve  times  their  volume  of  air,  the 
exact  proportion  depending  on  the  proportion  of  the  dif¬ 
ferent  individual  gases  that  enter  into  the  composition  of 
illuminating  gas.  For  instance,  hydrogen  requires  a 
smaller  volume  of  air  than  is  required  for  the  same  volume 
of  methane. 

We  have  seen  the  effect  of  burning  gas  without  pre¬ 
vious  mixture  with  any  portion  of  air,  and  the  effect  of 
burning  gas  after  passing  it  through  an  air  mixer  in  which 
about  three  times  the  volume  of  air  is  mixed  with  the  gas. 

If  all  of  the  air  necessary  completely  to  burn  the  gas 
were  thoroughly  mixed  with  it  previous  to  ignition  as  pri¬ 
mary  air,  the  combustion,  of  course,  would,  in  a  given  cham¬ 
ber,  be  instantaneous  and  would  constitute  what  we  call 


38 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


an  explosion.  It  is  this  principle  which  is  used  in  a  gas 
engine  or  in  all  so-called  internal  combustion  engines  in 
which  the  proper  mixture  of  gas  and  air  is  admitted  to  the 
cylinder,  the  port  of  admission  closed,  and  ignited  with  an 
electric  spark. 

Gas  engines  are  used  in  large  quantities,  particularly 
where  small  units  for  power  are  required.  They  can,  with 
safety,  be  set  in  almost  any  place  and  have  the  great  ad¬ 
vantage  over  a  steam  engine  and  boiler  in  the  small  amount 
of  space  required,  small  weight  of  apparatus,  no  dust  or 
ashes  and  freedom  from  danger  of  fire. 


Fig.  23 


Gas  Engine 


In  Philadelphia  such  gas  engines  are  used  to  operate 
the  large  pumps  to  force  water  at  increased  pressure 
through  the  high-pressure  water  mains  for  extinguishing  fires. 

Fourth:  Another  method  of  burning  gas  consists  of  supplying  pure 
oxygen  to  the  flame  instead  of  obtaining  oxygen  from  the 
air.  This  gives  a  short  flame  of  very  high  temperature 
and  is  used  for  a  number  of  purposes,  such  as  cutting 
through  steel  plate,  brazing,  welding,  etc. 

In  the  first  three  methods  described  atmospheric  air 
was  used  for  supporting  combustion,  and  with  each  volume 
of  oxygen  in  the  air  thus  used  there  were  supplied  also 
four  volumes  of  nitrogen,  an  inert  gas  which  had  to  be 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


39 


Test  of  High  -pressure  Water  System.  Power  Supplied  by  Use  of 
Internal  Combustion  Gas  Engines 

perature  is  achieved.  In  the  use  of  this  method  the  gas 
and  oxygen  are  supplied  by  two  separate  tubes,  the  mixing 
not  taking  place  until  very  near  the  point  of  combustion. 
Figure  25  shows  the  apparatus  in  use  and  indicates  the 
small  volume  to  which  the  flame  is  concentrated. 

In  the  first  method  of  burning  gas  for  illumination  without  previous 
mixture  with  air,  and  in  the  second  method  so  far  as  mantles  are  concerned, 
the  cardinal  principle  is  the  flame  temperature.  In  the  second  method 
(mantles  excepted)  and  third  method  the  cardinal  principle  is  the  total 


raised  to  the  same  temperature  as  the  other  products  of 
combustion,  and  passed  off  with  them,  removing  a  large 
quantity  of  heat  by  the  process  known  as  convection.  Not 
only  this,  but  it  enlarged  the  flame  volume  and,  therefore, 
defeated  the  localizing  of  combustion  by  which  high  tem- 


Fig.  24 


40 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


heat  evolved,  and  since  far  more  gas  is  used  in  the  second  and  third  methods 
than  in  the  first,  it  is  now  customary  throughout  the  United  States  to  read 
the  value  of  a  gas  according  to  its  total  heating  effect.  The  Public  Service 
Commissions  of  the  different  states,  whose  duty  it  is  to  test  the  quality  of 
the  gas  distributed  by  gas  companies,  have  generally  decided  that  the  test 
of  the  quality  of  the  gas  shall  be  its  total  heating  value,  and  this  test  is 
made  with  an  instrument  designed  to  show  this  value,  which  instrument 
is  called  a  calorimeter.  A  description  of  the  calorimeter  will  be  found  to 
follow  that  of  the  photometer  in  the  appendix. 

Fig.  25 


Illuminating  Gas,  after  Mixture  with  Oxygen,  being  used  for 
Welding  Purposes 


In  some  places,  as  in  Philadelphia,  for  reasons  to  be  shown  in  the  next 
chapter,  the  value  of  the  gas  is  still  determined  by  its  light-giving  qualities 
when  burned  through  a  lava  tip  without  previous  mixture  with  air;  but 
in  the  remainder  of  the  State  of  Pennsylvania,  as  in  most  other  states,  the 
Public  Service  Commission  has  decided  that  the  heating  value  rather  than 
the  photometric  value  of  the  gas  shall  decide  its  quality. 

It  is  important  to  observe  that  there  is  no  fixed  relation  between  the 
heating  value  of  a  gas  and  its  light-giving  value  when  burned  in  a  lava 
tip.  For  instance,  a  sixteen-candle-power  coal  gas  would  have  a  heating 
value  of  600  B.t.u.  per  cubic  foot,  while  a  two-  or  three-candle-power 
natural  gas  would  have  a  heating  value  of  nearly  1,000  B.t.u.  per  cubic  foot. 

The  advantage  of  all  these  methods  of  using  gas  is,  therefore,  that 
the  energy  of  the  fuels  and  oils  supplied  at  the  gas  works  is  stored  up  in 
the  gas  and  distributed  to  the  consumer  for  his  use  in  as  large  or  small 
quantities  as  he  desires,  and  in  this  form  permits  of  the  application  of  the 
heat  so  as  to  get  useful  work  from  a  greater  percentage  of  that  heat,  and 
at  less  cost,  than  can  be  obtained  in  any  other  way.  From  the  standpoint 
of  conserving  resources,  it  is  interesting  to  know  that  about  seventy  per 
cent,  of  the  energy  in  the  coal  can  be  delivered  to  the  consumer’s  meter  by 
gas. 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia  41 


The  number  of  uses  to  which  gas  is  adapted  cannot  be  enumerated 
here  and  we  must  be  satisfied  with  the  statement  that  there  are  over  one 
thousand  uses  to  which  gas  is  applied  in  the  streets,  offices,  homes,  factories, 
laboratories  and  the  sciences  and  arts  generally  in  Philadelphia.  The  fol¬ 
lowing  list  enumerates  a  few  as  showing  the  wide  diversity  of  its  uses: 


Brazing 
Case  hardening 
Caldron  furnaces  for: 
Rendering  lard 
Boiling  syrups 
Melting  wax 
Making  soaps 
China  kilns 
Coffee  roasting 
Candy  making 
Forge 

Glue  heaters 


Gas  engine 

Heating  machines  for: 

Ball  bearings 
Nuts,  bolts 

Needles,  small  blades,  etc. 
Tempering  writing  pens,  links, 
buttons,  etc. 

Japanning  ovens 
Pressing  irons 
Smokehouses 

Steam  boilers  (gas  heated) 

Tire  heaters 


SERVICES  OF  THE  GAS  COMPANY: 

After  the  gas  of  proper  quality  and  quantity  has  been  supplied  to  the 
consumers’  premises  by  the  company’s  mains,  a  very  important  branch  of 
the  company’s  work  still  remains. 

The  gas  company’s  work  is  not  done  until  the  people  of  the  city  have 
had  an  opportunity  to  get  all  the  benefits  that  may  be  obtained  by  them 
through  the  use  of  gas,  and  they  must  obtain  these  results  through  the 
exertions  of  the  gas  company,  with  the  least  possible  trouble  to  themselves 

COMPLAINT  MEN: 

There  are  representatives  of  the  company  on  hand  at  well-known  places 
ready  to  receive  any  notification  from  the  public  of  any  cause  for  com¬ 
plaint  in  the  use  of  gas.  The  telephone  directories  show  just  how  these 
people  can  be  reached  without  delay.  These  men  report  the  location  of 
the  trouble  and  its  nature  to  the  proper  department,  which  proceeds  at  all 
hours  of  the  day  or  night  to  apply  the  remedy.  The  gas  company  welcome 
these  complaints  eagerly  as  providing  a  means  by  which  a  further  knowledge 
of  all  phases  of  their  business  can  be  obtained,  and  through  which  more 
satisfactory  results  can  be  obtained  by  the  use  of  gas. 

For  replacing  broken  glassware  in  lamps  and  for  adjusting  and  repair¬ 
ing  appliances,  a  force  of  “Quick  Service”  men  is  maintained,  and  a  familiar 
sight  in  the  streets  of  our  city  is  one  of  the  “Quick  Service”  men  hurrying 
to  respond  to  a  call. 

NEW  BUSINESS: 

Representatives  of  the  company  should  cultivate  the  confidence  of  the 
citizens  to  know,  in  all  cases,  if  the  use  of  gas  appliances  prove  satisfactory. 
They  are  able  to  remedy  faults  in  operation  and  see  that  the  appliances 
give  continual  satisfaction  to  the  consumer. 


42 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


The  gas  company  is  also  quick  and  keen  to  make  the  citizens  acquainted 
with  other  uses  of  gas  that  would  conduce  to  their  comfort  and  convenience 
and  is  ready  to  show  all  modern  appliances  and  explain  their  uses.  This 
is  done  at  frequent  intervals. 


Fig.  26 


To  do  this  it  is  necessary  that  the  gas  company  should  carry  on  large 
experimental  laboratories  for  testing  new  appliances  to  make  sure  before 
recommending  them  to  their  consumers  that  the  appliances  can  be  depended 
upon  to  do  their  work  economically  and  safely,  and  that  they  are  well  made 
and  economical  also  in  space  and  first  cost.  The  gas  company  must  see  that 
the  apparatus  is  so  placed  and  so  connected  with  sufficient  pipe  as  to  do  its 
work  in  the  locality  selected. 

In  the  distribution  of  gas  there  must  be  constant  study  to  see  that  new 
pipe  of  sufficient  size  is  laid  to  reach  the  consumers  in  newly  built-up 
districts  as  soon  as  the  density  of  population  warrants  the  laying  of  pipe; 
that  the  flow  of  gas  through  the  mains,  even  in  the  older  and  more  densely 
populated  sections  of  the  city,  is  studied  constantly  to  determine  where 
changes  in  piping  shall  be  made  to  give  good  supply.  The  gas  company 
also  undertakes  to  give  constant  service  to  the  consumers’  lighting,  keeping 
all  fixtures  and  mantles  in  good  condition  and  visiting  them  at  regular 
intervals  to  see  that  they  are  so  maintained.  There  must  be  attractive 
offices  provided  in  locations  easily  reached  for  the  payment  of  bills,  for 
discussion  of  service  obtained  in  the  use  of  gas  and  for  inspection  of  new 
appliances  for  light,  heat  and  power.  There  must  also  be  provided  shops 
and  storage  yards  for  pipes,  meters  and  other  apparatus  to  reach  quickly 
any  portion  of  the  district  supplied  by  the  company.  There  must  be  shops 
for  the  testing  and  repairing  of  meters  to  be  sent  out  and  set  on  short 
notice. 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia  43 


The  result  of  all  this  is  that  the  citizen  is  so  accustomed,  when  turning 
on  a  cock  or  valve,  to  have  instantly  a  flow  of  gas  through  his  burner  or 
appliance  best  adapted  to  his  need,  that  little  thought  is  given  by  the  com¬ 
munity  at  large  to  the  plant  and  system  that  is  required  to  furnish  this 
uninterrupted  supply  of  light,  heat  and  power.  In  the  works  a  large  ex¬ 
pense  is  incurred  in  providing  extra  apparatus  which  may  be  put  in  opera¬ 
tion  at  short  notice  to  take  care  of  unusual  demands.  Enough  gas  to  last 
for  hours  is  already  made  and  stored  in  the  holders  ready  to  flow  out  through 
the  mains  to  the  consumer.  Large  quantities  of  raw  materials  for  gas  mak¬ 
ing  are  provided  and  stored  in  the  gas  works  to  insure  operation  in  times 
of  strikes  on  railroads,  in  the  mines,  or  congestion  on  the  railroads,  or  other 
causes  beyond  the  control  of  gas  companies. 

The  gas  companies  have  thus  impressed  on  the  minds  of  the  citizens 
a  reputation  of  always  having  their  commodity  ready  for  use,  independent 
of  disturbed  business  conditions,  storms,  floods  and  other  phenomena  that 
so  seriously  interfere  with  public  utilities  in  general  and  from  which  the 
gas  companies  are  secure  because  of  the  great  network  of  pipes  which  are 
laid  under  the  ground  and  go  thence  directly  into  the  houses  of  the  con¬ 
sumers. 

It  was  said  of  the  ancient  Egyptians  that  they  never  discussed  the  state 
of  the  weather  because  one  day  was  exactly  like  another.  It  is  the  desire 
of  the  gas  companies  to  enjoy  a  reputation  of  this  kind  by  having  their 
supply  continuous  through  years  of  service  and  always  the  same  in  quality. 


In  cities  today  gas  is  the  principal  agent  employed  for  cooking.  Above  are 
shown  types  of  gas  ranges  such  as  are  found  in  practically  all  city  homes 


P hiladelphia  Qas  Works 


Gas  manufacture  and  distribution  was  first  started  in  Philadelphia 
in  1836  and  has  been  in  continuous  operation  for  the  ensuing  eighty-one 
years.  On  February  10,  1836,  forty-six  public  lamps  on  Schuylkill  Second 
Street  (now  Twenty-first  Street)  and  nineteen  private  burners  in  the  only 
two  dwellings  that  were  prepared  for  the  introduction  of  gas,  were  lighted 
for  the  first  time. 

The  business  of  gas  manufacture  and  sale  in  this  city  has  always  been 
owned  by  the  city  itself.  In  this  it  is  unlike  any  other  large  city  in  this 
country  and  has  brought  about  one  peculiar  result, — there  has  never  been 
any  competition  in  Philadelphia  in  the  sale  of  gas  nor  more  than  one  system 
of  mains  in  the  streets.  The  City  of  Philadelphia  has  never  granted  a  fran¬ 
chise  or  allowed  any  other  company  to  sell  gas  herein;  whereas,  in  other 
cities  a  number  of  competitive  companies  have  been  granted  franchises  from 
time  to  time,  and  without  exception  they  have  later  joined  together  into 
one  large  company  controlling  the  sale  of  gas  for  the  whole  city. 

A  few  items  of  the  history  of  the  Philadelphia  Gas  Works  are  to  be 
noted.  In  the  early  years  of  gas  lighting,  the  boundaries  of  the  city  were 
the  two  rivers  and  South  Street  and  Vine  Street.  The  communities  lying 
without  these  boundaries  were  not  supplied  with  gas  from  the  city  works 
and  they,  therefore,  had  to  build  works  of  their  own,  and  in  this  way  gas 
works  were  started  in  Frankford,  Manayunk,  Germantown,  Moyamensing, 
Bridesburg,  Spring  Garden,  Northern  Liberties,  Kensington,  and  because 
of  its  remoteness,  a  special  municipal  plant  for  the  House  of  Correction. 
As  Philadelphia  expanded  its  boundaries,  these  smaller  communities  were 
incorporated  into  the  City,  and  the  pipes  of  the  Philadelphia  Gas  Works 
were  extended  to  connect  with  the  pipes  of  these  smaller  communities.  Each 
of  these  smaller  companies  in  turn  was  incorporated  into  the  city  gas 
works,  with  the  exception  of  the  Northern  Liberties  and  the  small  municipal 
plant  at  the  House  of  Correction  in  Holmesburg  which  supplies  a  small 
number  of  houses  in  the  immediate  vicinity.  The  Northern  Liberties  Gas 
Company  still  continues  to  sell  gas  in  its  district.  The  City  of  Philadel¬ 
phia  owns  a  portion  of  the  stock  of  this  company  and  there  is  no  attempt 
on  the  part  of  the  city  gas  works  to  invade  the  Northern  Liberties  district, 
nor  can  the  Northern  Liberties  Gas  Company  go  beyond  its  boundaries  into 
other  city  streets. 

The  result  of  the  final  closing  of  these  smaller  outlying  plants 
has  been  to  release  their  sites,  formerly  occupied  by  them  as  works  and 
holder  stations,  for  the  erection  of  large  outlying  gas  holders  to  which  gas 
is  pumped  at  high  pressure  from  the  works  through  large  pumping  mains, 
independent  of  the  distribution  mains.  The  use  of  these  holders  in  the 
locations  so  fixed  many  years  ago  is  important  because  it  permits  an  en¬ 
largement  of  the  small  systems  of  distribution  mains  so  that  gas  can  be 
furnished  to  the  entire  city  with  smaller  changes  in  pressure  than  wTould 
44 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia  45 

have  been  possible  if  all  of  the  gas  had  been  sent  out  direct  from  the  holders 
at  the  works.  If  this  latter  course  had  been  adopted  during  the  eighty-one 
years,  it  would  have  been  necessary  to  have  enlarged  the  entire  system  of 
mains  several  separate  times  at  enormous  expense.  These  outlying  holders 
are  now  located  at: 

Mifflin  Street  between  Eighth  and  Ninth  Streets. 

Market  Street  between  Twenty-second  and  Twenty-third  Streets. 
Chestnut  Street  between  Forty-seventh  and  Forty-eighth  Streets. 
(Figure  27.) 

Ninth  Street  between  Norris  and  Diamond  Streets. 

G  and  Venango  Streets. 

Belfield  Avenue  and  Collom  Street,  Germantown. 

Shurs  Lane  and  Main  Street,  Manayunk. 

Fig.  27 


Gas  Holder  Station 


The  first  gas  works  was  located  on  both  sides  of  Market  Street  along 
the  Schuylkill  River.  In  1850  the  necessity  for  additional  gas  supply  was 
clearly  shown  and  it  was  decided  to  build  a  new  gas  works  at  Passyunk 
Avenue  and  Schuylkill  River.  This  works  was  started  on  December  13, 


46 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


1854,  and  large  mains  were  laid  in  the  ground  to  connect  these  works  with 
the  system  of  mains  radiating  from  the  works  on  Market  Street. 

In  1875  the  demand  for  additional  gas  in  the  northern  section  of  the 
city  was  met  by  the  building  and  starting  up  of  the  gas  works  located  at 
Tioga  Street  and  the  Delaware  River. 

In  1897  it  became  evident  to  the  Select  and  Common  Councils  of  the 
City  that  the  operation  of  the  gas  works  was  not  being  conducted  economic¬ 
ally,  nor  was  the  money  being  appropriated  by  them  out  of  the  general 
funds  of  the  city  sufficient  in  quantity  to  enlarge  the  works  and  distributing 
mains  so  as  to  keep  pace  with  the  additional  demands  for  gas  due  to  growth 
of  the  city.  The  gas  works  was  considered  a  very  valuable  asset  which 
Councils  were  reluctant  to  dispose  of  by  sale  and,  accordingly,  it  was  de¬ 
cided  to  lease  the  gas  works  to  The  United  Gas  Improvement  Company, 
which  organization  was  known  to  be  experienced  in  the  operation  of  gas 
works  by  reason  of  owning  and  operating  works  in  other  cities. 

Under  the  agreement  of  the  lease  the  lessees  were  required  to  provide 
all  the  gas  used  by  the  city  for  illumination  in  its  offices,  fire  houses,  schools, 
etc.,  free  of  charge;  to  supply  the  gas  free  of  charge  and  to  light,  extinguish 
and  maintain  in  good  order  all  of  the  street  lamps  in  use  at  the  time  of 
the  lease  and  to  erect  300  additional  lamps  each  year;  to  expend  at  least 
$15,000,000  in  improvements,  extensions  and  betterments  to  the  plant  dur¬ 
ing  the  thirty  years’  duration  of  the  lease;  to  furnish  a  good  gas  of  at  least 
twenty-two  candle-power,  as  measured  at  a  testing  station  located  not  less 
than  one  mile  from  the  works;  to  collect  all  the  money  due  from  the  sale 
of  gas  to  private  consumers,  and  to  pay  into  the  City  Treasury  all  the  money 
received  over  ninety  cents  per  thousand  cubic  feet  of  gas  sold  during  the 
first  ten  years,  over  eighty-five  cents  for  the  next  five  years,  over  eighty 
cents  for  the  next  five  years,  and  over  seventy-five  cents  for  the  last  ten  years. 

The  Councils  of  the  City  retained  the  right  to  fix  the  price  of  gas, 
which  it  was  agreed  should  not  be  over  one  dollar  per  thousand  cubic  feet. 
In  this  way  the  City  Councils  could  choose  between  making  the  rate  for 
the  sale  of  gas  equal  to  the  amount  that  the  company  was  to  receive,  thereby 
reducing  the  gross  revenue  of  the  City  approximately  $2,000,000  per  year 
over  what  they  would  receive  if  the  rate  were  maintained  at  one  dollar  per 
thousand  cubic  feet. 

Another  article  of  agreement  in  this  lease  was  that  the  original  gas 
works  site  at  Market  Street  and  the  Schuylkill  River  should  be  abandoned 
as  a  gas  manufacturing  station.  This  was  accomplished  in  1898,  and  there 
are  at  present  two  manufacturing  stations,  one  at  Passyunk  Avenue  and 
the  Schuylkill  River — known  as  Station  “A,”  and  one  at  Tioga  Street  and 
the  Delaware  River — known  as  Station  “B.”  At  each  of  these  stations 
both  coal  and  water  gas  are  made  and  the  gases  mixed  so  as  to  insure  a 
twenty-two  candle-power  gas  delivered  at  the  respective  testing  stations. 
The  City  of  Philadelphia  has,  therefore,  adhered  to  rating  the  value  of  its 
gas  according  to  the  candle  power,  while  most  of  the  other  cities  in  this 
country  now  rate  their  gas  according  to  its  heating  value.  At  the  time  the 
lease  was  executed  between  the  City  of  Philadelphia  and  the  company 
operating  the  gas  works,  no  company  in  the  country  rated  its  gas  according 
to  its  heating  value.  The  candle  power  of  the  gas  is  measured  daily  by  the 
City’s  Gas  Inspector  who  also,  upon  complaint  of  any  consumer,  will  test 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


47 


his  meter,  the  company  maintaining  two  gas-testing  stations  and  a  meter¬ 
proving  station  for  the  use  of  the  city  officials. 

In  the  previous  chapters  we  have  described  and  illustrated  the  chemical 
and  mechanical  processes  used  in  gas  manufacture.  We  have  there  shown 
the  generation  of  gas,  its  cleaning  and  purification  as  a  continuous  process. 
In  a  gas  works  the  size  of  those  required  to  supply  Philadelphia,  each  of 
these  processes  occupies  separate  and  detached  buildings.  Each  of  these 
processes  requires  several  large  buildings  in  each  works  and  the  care  and 
detail  necessary  to  obtain  a  high  degree  of  efficiency  could  not  be  dwelt  on 
in  detail  in  a  pamphlet  of  this  kind. 

The  consumption  of  gas  in  Philadelphia  on  a  cold  winter  day  in  1917 
would  have  been  sufficient  to  have  furnished  one  Welsbach  burner,  such 
as  is  used  in  house  lighting,  with  gas  for  continuous  burning  throughout 
the  twenty-four  hours  of  the  day  for  about  1,725  years. 

At  the  gas-manufacturing  stations  there  must  be  carried  in  stock  at 
all  times  millions  of  gallons  of  oil,  and  the  stocks  of  coal  approach  100,000  tons. 

The  gas  stored  in  the  holders  at  sunset  is  generally  sufficient  to  last 
throughout  the  night  until  the  following  morning. 

The  system  of  distributing  mains  of  the  Philadelphia  Gas  Works  now 
consists  of  1,551  miles,  of  which  1,409  miles  are  over  three-inch.  These 
mains,  if  placed  in  one  straight  line,  would  reach  from  Philadelphia  to 
Vicksburg  on  the  Mississippi  River.  The  large  mains  are  called  “trunk 
mains;”  of  these  a  main  thirty  inches  in  diameter  extends  from  Richmond 
and  Tioga  Streets  to  Front  and  Market  Streets,  a  length  of  4.2  miles. 
Another  thirty-inch  main  extends  from  Station  “A,”  at  Passyunk  Avenue 
and  the  Schuylkill  River,  in  Passyunk  Avenue  to  Sixteenth  Street,  up  Six¬ 
teenth  Street  to  Lehigh  Avenue  and  west  to  Twenty-second  Street,  a  dis¬ 
tance  of  6.5  miles.  From  the  holder  station  at  G  and  Venango  Streets  a 
48-inch  main  extends  under  the  Pennsylvania  Railroad  north  to  Erie  Ave¬ 
nue,  a  distance  of  1,800  feet.  There  are  forty -five  miles  of  twenty-inch 
mains  in  the  distribution  system  and  from  these  large  mains  connections 
are  made  to  carry  the  gas  along  each  street  of  the  City,  the  mains  being 
connected  in  such  a  way  as  to  support  each  other  in  maintaining  an  ade¬ 
quate  flow  of  gas  without  great  changes  in  pressure.  In  addition  to  these 
mains  another  system,  leaving  each  works,  thirty  inches  in  diameter  and 
reducing  finally  at  the  outlying  stations  to  sixteen  inches  in  diameter,  has 
been  laid  so  that  gas  can  be  pumped  from  either  of  the  manufacturing 
stations  to  any  one  of  the  outlying  holder  stations,  or  from  one  works  into 
the  holders  of  the  other  works,  without  in  any  way  interfering  with  the 
pressures  in  the  gas-distribution  mains.  These  holder  stations  must  dis¬ 
charge  their  gas  into  the  distributing  mains  without  undue  loss  of  pressure, 
and  it  is  therefore  clear  that,  unless  a  holder  station  is  to  be  accompanied 
with  the  heavy  expense  of  providing  very  large  diameter  mains  connecting 
with  the  distribution  system,  that  the  location  of  these  new  holder  stations 
shall  be  determined  by  the  condition,  size  and  pressure  in  the  gas  mains 
then  existing  in  the  streets. 

METERS: 

No  business  is  so  intimately  associated  with  the  entire  body  of  citizens 
as  that  of  supplying  gas,  except  the  still  more  important  business  of  sup- 


48  The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


plying  water.  In  this  City  there  were,  according  to  the  Chamber  of  Com¬ 
merce  report  of  December  31,  1916,  370,000  residences;  to  supply  these  as 
well  as  stores,  factories,  offices,  etc.,  there  were  in  place  at  the  same  date 
399,356  gas  meters,  not  including  those  placed  by  the  Northern  Liberties 
Company  and  the  municipal  plant  at  Holmesburg.  The  business  of  keeping 
the  records  and  accounts  of  this  number  of  consumers  is  one  that  requires 
application  of  the  most  efficient  methods  in  order  that  all  consumers  shall 
be  treated  fairly;  that  no  opportunity  shall  be  lost  for  instructing  and  en¬ 
couraging  them  in  the  advantages  and  comforts  to  be  obtained  from  the 
use  of  gas  by  reason  of  new  applications  and  inventions,  and  that  the  records 
of  none  of  the  consumers  be  lost,  notwithstanding  the  great  proportion  of 
the  citizens  who  move  from  one  premises  to  another  throughout  the  year. 
If  one  could  inspect  these  records  he  would  be  led  to  believe  that  the  no¬ 
madic  character  of  our  citizens  is  strongly  established.  New  houses  are 
being  erected  at  an  average  of  about  7,000  each  year  and  each  of  these 
houses  must  be  connected  to  the  gas  mains  with  service  and  meter.  Fre¬ 
quently,  mains  must  be  laid  in  streets  where  none  was  laid  before,  and  this 
should  be  done  before  the  final  paving.  The  work  of  the  Distribution  De¬ 
partment,  therefore,  is  not  confined  to  any  one  portion  of  the  City  but  exists 
in  every  street  and  avenue.  Their  stockyards,  storehouses  and  workshops 
must  be  located  in  each  district;  their  working  gangs  will  be  found  here 
and  there  continually  throughout  the  City  (Figure  28) : 


Fig.  28 


Laying  Large  Gas  Mains  in  City  Streets 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


49 


The  distribution  shops  and  yards  are  located  as  follows : 

1931  South  Ninth  Street. 

1615  North  Ninth  Street. 

4650  Market  Street. 

20  West  Maplewood  Avenue,  Germantown. 
4427  Frankford  Avenue. 


In  the  City  the  gas  meters  are  taken  out  at  regular  intervals  and  tested. 
This  requires  that  there  shall  be  on  hand  a  great  number  of  extra  meters, 
and  a  large  force  of  men  employed  continuously  in  this  periodic  testing  of 
them.  Such  meter-testing  stations  are  located  at: 

1931  South  Ninth  Street. 

1615  North  Ninth  Street. 

4650  Market  Street. 

20  West  Maplewood  Avenue,  Germantown. 

4427  Frankford  Avenue. 

19th  Street  and  Allegheny  Avenue. 


Offices  are  open  in  the  districts  for  the  collection  of  bills,  for  receiving 
orders  for  the  setting  of  meters  to  supply  gas  to  new  consumers,  for  receiv¬ 
ing  notices  of  removal  of  consumers  from  their  premises,  and  for  such 
complaints  as  occur  from  various  causes  from  time  to  time.  Such  offices 
are  located  at: 


Main  Office . 

Down  Town . 

Spring  Garden.  .  . 
West  Philadelphia 

Frankford . 

Kensington . 

Germantown . 

Manayunk . 

Bridesburg . 


Broad  and  Arch  Streets. 
Broad  and  Tasker  Streets. 
1706  North  Broad  Street. 
135-137  South  52d  Street. 
4417-21  Frankford  Avenue. 
2209-11  North  Front  Street. 
5534  Germantown  Avenue. 
4236  Main  Street. 

2661  Bridge  Street. 


At  each  of  these  offices  there  is  an  exhibit  of  gas  fixtures,  appliances 
and  lamps  in  great  variety.  Competent  employees  are  in  charge  to  explain 
the  uses  and  adaptability  of  the  appliances  and  to  arrange  for  their  installation. 

These  stores  come  under  the  supervision  of  the  New  Business  Depart¬ 
ment.  This  department  is  responsible  also  for  the  men  who  visit  the  con¬ 
sumers  at  their  homes  to  sell  gas  appliances  and  lamps;  for  the  Burner 
Maintenance  Division  which  cares  for  lamps  that  have  been  installed  on 
maintenance  contracts  and  for  the  Instruction  Division  which  consists  of 
women  who  visit  the  housewives  to  show  how  they  can  get  the  best  results 
from  the  appliances  they  have  bought. 

Finally,  the  Advertising  Department  keeps  constantly  before  the  public 
the  advantages  to  be  derived  from  the  use  of  gas,  and  this  is  done  by  per¬ 
sistent  and  continuous  advertising  in  the  daily  papers,  by  small  pamphlets 
bearing  on  the  subject,  by  window  displays  and  special  exhibits  in  connec¬ 
tion  with  national,  state  and  city  exhibitions,  and  exhibits  devoted  exclu¬ 
sively  to  gas  appliances. 


0 . 


^Appendix 

t 


Photometer 


% 


The  intensity  of  light  from  a  gas  flame  is  measured  in  a  horizontal 
direction  on  an  instrument  called  a  “photometer”  and  is  expressed  in  terms 
of  the  number  of  standard  candles  that  would  be  required  to  be  consumed 
to  give  the  same  intensity  of  light  when  measured  in  a  horizontal  direction. 

The  standard  candle  is  the  unit  for  measurement  of  all  luminous 
flames.  It  is  a  sperm  candle  made  according  to  specifications  set  forth  by 
an  Act  of  Parliament  in  Great  Britain  in  1871,  which  describes  in  com¬ 
plete  detail  how  all  parts  of  the  candle  shall  be  prepared  and  assembled  and 
the  care  to  be  observed  in  its  burning.  This  standard  candle  is  the  only 
unit  of  light  that  has  so  far  received  the  official  sanction  of  any  central 
government  and  it  has  been  in  use  in  photometrical  work  for  forty-five 
years.  It  is  not  now,  however,  as  much  used  as  formerly  because  of  the 
length  of  time  required  to  make  a  test  with  candles  and  the  difficulty  of 
keeping  the  candles  in  proper  condition  in  warm  climates,  and  to  the  fact 
also  that  the  source  of  supply  is  solely  in  London. 

Figure  29  shows  a  photometer  mounted  on  a  table. 


Fig.  29 


Gas  Photometer 


53 


54  The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


Accordingly,  Sir  Vernon  Harcourt  invented  what  is  known  as  the 
Ten  Candle  Harcourt  Pentane  Lamp  which,  burning  a  very  carefully 
prepared  hydrocarbon  oil  called  pentane,  can  be  made  to  give  a  luminous 
surface  of  steady  uniform  value  of  approximately  ten  candles.  This  lamp 
has  been  in  use  for  some  years,  has  undergone  extensive  tests  and  has  now 
received  the  approval  of  the  United  States  Bureau  of  Standards  at  Wash¬ 
ington,  and  the  committee  of  the  House  of  Parliament  in  England. 

The  photometer  consists  of  a  graduated  bar  sixty  or  one  hundred  inches 
long,  to  the  right  of  which  is  shown  the  burner  from  which  is  emitted  the  flame 
to  be  tested,  and  at  an  equal  distance  from  the  center  of  the  bar,  at  the  left 
end,  a  ten-candle  pentane  lamp.  The  plumb-bobs  are  used  to  check  the  dis¬ 
tances  from  the  center  of  the  bar.  On  the  table  on  the  burner  side  is  located 
a  meter  through  which  the  gas,  in  passing  to  the  burner,  is  carefully  meas¬ 
ured,  a  thermometer  being  inserted  in  the  meter  for  determining  the  tem¬ 
perature  of  the  gas;  and  a  small  gas  governor  for  securing  uniform  pressure 
throughout  the  test. 

Fig.  30 


Disc  Box 

Rolling  on  a  small  double  track,  to  which  is  fastened  a  graduated  bar, 
is  the  disc  box  (Figures  30  and  31).  It  consists  of  three  pieces  of  white 
paper.  The  middle  piece  is  of  thicker  paper,  uniform  in  quality  and  finish 
on  both  sides,  and  has  a  star  stamped  from  its  center.  On  each  side  of  this 
is  placed  a  thin  sheet  of  white  rice  tissue  paper.  These  three  pieces  are  cut 
round  and  pressed  between  two  discs  of  white  French  plate  glass,  so  that  their 
surfaces  are  flattened  out.  The  star  portion  of  the  disc,  being  thinner,  is 
more  translucent  than  the  surrounding  field,  and  when  held  up  to  the  light 
appears  brighter.  At  the  back  of  the  disc  holder  and  fixed  at  an  angle  of 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


55 


sixty  degrees  with  the  plane  of  the  holder  are  two  small  mirrors,  one  on 

each  side,  so  that  when  the  disc  holder  is  placed  in  the  disc  box  and  the 

sight  piece  “K”  is  fastened  to  the  front  of  the  disc  box,  an  observer  looking 
through  can  see  the  reflected  light  from  the  disc  in  the  mirror  on  each  side. 
The  disc  box  being  in  place,  if  one  of  the  lights  is  screened,  the  observer 

upon  looking  at  the  mirror  on  the  side  towards  the  unscreened  light  will 


Fig.  31 


Details  of  Disc  Box  and  Sight  Piece 


see  a  bright  reflection  from  the  disc  paper,  except  at  the  point  of  the  star 
where  the  translucent  paper  will  permit  certain  of  the  rays  to  go  through  and 
consequently  will  show  the  star  as  darker  than  the  surrounding  paper.  If 
now,  both  lights  being  lit,  the  disc  is  placed  at  that  point’  in  the  bar  nearer 
the  weaker  light,  where  the  amount  of  light  from  each  side  falling  on  the 
disc  is  the  same,  the  amount  of  light  that  passes  through  the  translucent 
paper  on  one  side  will  be  equal  to  the  amount  of  light  passing  through  the 
translucent  paper  from  the  other  side  and  the  reflection  from  the  star  will 
be  equal  to  the  reflection  from  the  paper  and  the  star  will  appear  equally 
bright  in  both  mirrors.  The  pointer  at  the  bottom  of  the  box  will  now 
show  the  relative  distance  that  the  disc  is  from  each  light  and,  therefore,  the 
number  of  times  that  the  gas  flame  is  brighter  than  the  flame  of  the  pentane 
lamp  can  be  calculated  by  the  rule  that  the  intensity  of  light  from  each 
source  is  inversely  proportional  to  the  square  of  the  distance.  That  is  to 
say,  if  the  disc  is  found  to  be  thirty-six  inches  equals  three  feet  from  the  gas 
flame  and  twenty-four  inches  equals  two  feet  from  the  pentane  lamp  when 
equal  illumination  is  observed  on  both  sides  of  the  disc,  the  intensity  of  the 


56  The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


Fig.  32 


Sight  Piece  "K" 


gas  flame  will  be  (2*  =  i  =  2.25)  two  and  a  quarter  times  that  of  the  ten- 
candle  pentane  lamp,  or  the  gas  will  be  22.5  candle  power. 

The  candle  power  of  the  gas  at  the  observed  rate  of  consumption  must 
be  corrected  in  proportion  to  what  it  would  have  been  if  the  consumption 
had  been  shown  to  be  at  the  rate  of  five  cubic  feet  per  hour  on  the  meter; 
and  there  must  also  be  a  correction  for  the  atmospheric  pressure  and  stand¬ 
ard,  which  is  taken  at  thirty  inches  mercury  by  the  barometer. 


Calorimeter 

% 

The  heating  value  of  a  gas  is  defined  by  the  total  heating  effect  pro¬ 
duced  by  the  complete  combustion  of  the  gas  with  air  of  the  same  tempera¬ 
ture,  the  products  of  combustion  being  brought  to  the  initial  temperature 
of  the  gas  and  air. 

The  heating  effect  is  stated  in  terms  of  British  thermal  units. 

The  British  thermal  unit  is  the  amount  of  heat  required  to  raise  one 
pound  of  water  one  degree  Fahrenheit  from  its  temperature  of  greatest 
density  39.1°. 

Figure  33  shows  a  calorimeter  complete  with  its  auxiliaries  for  deter¬ 
mining  the  heating  value  of  illuminating  gas. 

Fig.  33 

I'.. 


Junker’s  Type  Calorimeter 

The  gas  first  enters  the  meter  at  the  left,  which  is  of  wet  experimental 
type,  having  water  as  the  lower  confining  surface  in  its  measuring  compart¬ 
ment.  The  level  of  this  water  may  be  raised  or  lowered,  as  indicated  on  the 
water  gauge  at  the  side.  A  drum  having  four  chambers  revolves  on  a  hori¬ 
zontal  axis  centrally  located  from  front  to  back  of  the  meter,  the  front  end 
of  this  axis  projecting  through  the  meter  case  and  bearing  a  hand.  This 
hand  travels,  therefore,  directly  with  the  drum’s  rotation,  and  indicates 

57 


58  The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


on  the  dial  fractional  revolutions,  while  other  hands  geared  to  it  register 
complete  revolutions  (each  one-tenth  of  a  cubic  foot)  and  multiples  by  ten 
thereof. 

The  four  drum  compartments  are  separated  by  partitions  warped  like 
the  surface  of  an  Archimedes  screw,  the  water  level  being  at  such  a  height 
that  the  upper  chambers  are  filled  with  gas  and  the  lower  with  water.  With 
Archimedes  (using  water),  power  was  applied  to  revolve  the  screw  and 
caused  the  water  to  flow  through.  With  the  wet  meter,  conversely,  using 
water  below  and  gas  above  the  gas  flows  through  under  pressure,  supplying 
the  needed  power,  and  the  screw  (or  drum)  is  made  to  revolve.  Advantage 
is  taken  of  this  revolution  to  register  volume  passing.  The  meter  is  provided 
with  a  thermometer  to  indicate  the  temperature  of  the  gas  during  measur¬ 
ing,  while  the  barometric  pressure  is  determined  at  the  same  time  in  order 
that  the  gas  passing  as  indicated  by  the  meter  may  have  its  volume  cor¬ 
rected  to  standard  conditions,  namely,  thirty  inches  barometer  and  sixty 
degrees  Fahrenheit. 

The  gas  next  passes  to  the  small  cylindrical  instrument  shown.  This 
is  a  wet  governor  with  a  gas  bell  over  water  built  upon  the  general  idea  of 
the  works  governor  before  described.  On  its  top,  weights  are  placed  to 
maintain  the  pressure  of  the  gas,  leaving  it  exactly  uniform  as  indicated 
by  its  U-gauge  so  that  the  transfer  of  heat  from  the  gas  to  the  water  flowing 
through  the  calorimeter  will  be  at  a  steady,  uniform  rate. 

The  gas  next  passes  to  the  Bunsen  burner  inserted  beneath  the  calor¬ 
imeter  proper,  this  burner  having  a  cock  by  which  the  rate  of  gas  flow  can 
be  controlled  between  the  limits  fixed  for  most  efficient  performance  of  the 
calorimeter,  usually  with  illuminating  gas  from  five  to  seven  feet  per  hour. 

This  Bunsen  burner  has  a  cap  which  causes  the  flame  to  spread  at  its 
top,  so  as  to  play  closer  to  the  combustion  walls.  The  Bunsen  tube  is  held 
vertical  with  its  axis  coinciding  with  that  of  the  cylindrical  combustion 
chamber,  as  shown  in  Figure  34,  by  means  of  a  clamp  arm  sliding  on  a 
flattened  rod,  against  which  it  is  set  by  a  screw.  After  the  gas  is  lighted 
and  adjusted  with  primary  air  until  all  luminous  flame  just  ceases,  the 
Bunsen  is  inserted  until  the  flame  is  five  or  six  inches  up  the  chamber.  A 
small  mirror  placed  at  an  angle  near  the  bottom  shows  whether  the  flame 
continues  to  burn  properly  and  to  permit  further  adjustment  of  the  primary 
air  if  necessary. 

The  products  of  combustion  rise  inside  the  combustion  cylinder  (Fig¬ 
ure  34)  until  they  strike  the  inner  hood  and  then  pass  down  through  the 
tubes  to  the  lower  annular  compartment  and  out  through  the  outlet  flue 
to  the  air.  In  the  passage  up  the  inside  of  the  cylinder  and  through  the 
tubes  they  impart  their  heat  to  the  surrounding  walls  and  emerge  from  the 
apparatus  at  a  temperature  either  exactly  or  very  nearly  that  of  the  enter¬ 
ing  water,  which  should  be  the  same  as  that  of  the  air.  This  may,  in  part, 
be  controlled  by  the  damper  shown,  the  exhaust  thermometer  indicating 
correctness  of  the  temperature.  As  water  is  formed  by  the  combustion  of 
the  hydrogen  in  the  gas  it  is  condensed  during  this  cooling  and  runs  off 
through  the  small  pipe  tapped  into  the  ring  closing  the  bottom  of  the  lower 
annular  compartment,  dropping  into  a  small  measuring  glass,  for  purpose 
of  record. 

The  calorimeter  proper  is  best  understood  through  a  reference  to  the 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia  59 


Fig.  34 


Details  of  Junker’s  Type  Calorimeter 


60  The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


sectional  view  given  in  Figure  34,  paying  particular  attention  to  the  arrows 
indicating  the  direction  of  gas  and  water  flow.  Its  outer  diameter  is  about 
seven  inches,  its  diameter  inside  the  combustion  chamber  is  four  inches. 
The  body  of  the  instrument  over  all  is  about  twenty-eight  inches,  and  the 
total  height,  from  bottom  of  legs  to  top  of  inlet  water  cup,  fifty-six  inches. 

It  is  constructed  of  copper  sheets  with  fittings  of  brass.  Its  entire  outer 
surface  is  nickeled  and  highly  polished  to  prevent  heat  loss  by  radiation. 
The  legs,  water  connections  and  circular  nest  of  condensing  tubes  are  remov¬ 
able  for  repair  or  examination.  The  tripod  legs  are  adjustable  in  length 
to  secure  verticality,  using  plumb-bob  shown  above  water  regulating  valve. 

The  outer  polished  casing  of  the  calorimeter  body  has  a  clearance  of 
about  one-half  inch  from  the  outer  casing  of  the  ring  nest  of  condenser 
tubes,  and  this  annular  clearance  space  (see  horizontal  section  below  in  Fig¬ 
ure  34)  is  filled  with  air  for  heat  insulation. 

The  flow  of  water  through  the  calorimeter  is  regulated  by  a  valve  with 
a  hand  moving  over  a  graduated  arc.  Usually,  the  flow  is  so  adjusted  as  to 
secure  a  fifteen-degree  F.  rise  in  temperature  of  the  outlet  over  the  inlet 
thermometers.  Below  this  valve  is  a  “T”  head  cock  through  which  all  water 
is  drawn  from  the  calorimeter  when  it  is  to  be  put  out  of  use. 

Below  the  bulb  of  the  outlet  thermometer  is  shown  a  series  of  curved 
lines.  These  represent  sections  of  bafflers,  in  the  shape  of  convex  discs  with 
a  horizontal  slot  cut  part  way  across  each.  By  arranging  these  slots  at 
angles  with  each  other  any  direct  currents  are  broken,  and  thus  the  tem¬ 
perature  of  the  flow  as  a  whole  is  quite  uniform  while  being  registered  at 
the  outlet  water  thermometer. 

Since  the  temperature  of  the  atmosphere  in  the  room  and  of  the  inflow¬ 
ing  water  are  kept  as  nearly  alike  as  possible,  there  will  be  no  rise  in  the 
temperature  of  the  inlet  water  after  measurement  due  to  the  air  in  the  room. 

The  outlet  or  hot-water  funnel  is  provided  with  a  two-way  cock  by 
which  during  the  process  of  measuring  the  weight  of  water  heated,  this 
hot  water  may  be  instantly  diverted  from  the  “waste”  to  the  “bucket”  or 
vice  versa. 

On  the  right  of  Figure  33  is  shown  the  weighing  device  used  with  the 
calorimeter.  It  consists  of  a  balance,  on  one  platform  of  which  is  placed 
the  copper  bucket  to  catch  the  heated  water,  and  on  the  other  are  placed 
the  pound  weights  to  counterbalance  or  weigh  it.  The  exact  balance  is 
obtained  by  a  sliding  counterweight  which  registers  to  one-hundredth  of  a 
pound. 

When  it  is  desired  to  make  a  determination  of  the  calorific  value  of 
a  gas,  the  apparatus  is  set  up  on  a  firm  base  in  such  a  position  that  it  can  be 
readily  supplied  with  the  gas  to  be  tested  and  with  flowing  water.  The 
thermometers  provided  for  the  purpose,  which  are  graduated  in  tenths  of 
degrees  Fahrenheit  from  usual  room  temperatures  (about  60°)  to  110°, 
should  be  inserted  in  the  proper  openings,  as  shown  in  Figure  34.  Connec¬ 
tion  is  then  made  with  the  water  supply  by  means  of  rubber  tubing  slipped 
over  the  nipple  of  the  water  inlet.  A  rubber  tube  leading  to  a  drain  is 
slipped  over  the  nipple  marked  “overflow,”  another  tube  is  slipped  on  the 
nipple  leading  from  the  hot-water  funnel  to  water  “waste,”  while  a  fourth 
tube  is  supplied  to  lead  from  hot-water  funnel  to  bucket.  Water  being 
turned  on  flows  to  the  inlet  cup  and  thence  down  past  the  bulb  of  the  inlet 


The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia 


61 


water  thermometer,  through  the  water-regulating  valve  and  into  the  annular 
space  at  the  bottom  of  the  tubes.  It  rises  around  the  annular  nest  of  tubes, 
absorbing  heat  from  their  outer  surfaces,  through  the  conical  passage  and 
into  the  central  riser,  in  which  it  is  thoroughly  mixed  by  the  baffle  rings, 
then  around  the  bulb  of  the  outlet  water  thermometer  inserted  into  the  top 
of  the  riser  and  thence  by  the  side  pipe  to  the  cup  in  which  it  rises  until  it 
overflows  into  the  funnel  and  passes  away  through  the  two-way  cock.  Water 
should  be  admitted  into  the  outlet  cup  at  a  faster  rate  than  that  at  which 
it  is  passed  through  the  water-regulating  valve  so  that  this  cup  continually 
overflows  into  the  larger  cup  and  to  the  drain.  In  this  way  a  constant  head 
for  the  supply  of  water  is  maintained,  and  as  the  water  also  overflows  into 
the  funnel  on  the  outlet  at  a  constant  height,  the  effective  head  is  constant 
and  the  water  must  flow  through  at  a  constant  speed  as  long  as  the  water¬ 
regulating  valve  remains  set  at  any  given  opening. 

The  heating  value  of  the  gas  is  obtained  by  passing  a  given  volume, 
say  one  cubic  foot  of  it  (corrected  to  60°  F.  and  30  inches  barometer) 
through  the  meter,  and  collecting  the  amount  of  water  heated  during  the 
exact  time  the  gas  was  being  metered.  This  water  is  weighed  in  pounds,  its 
rise  in  temperature  noted  in  degrees  Fahrenheit,  and  the  product  of  these 
two  quantities  will  give  the  number  of  British  thermal  units  contained  in 
the  one  cubic  foot  of  gas. 


Educational  Eamphlets 

Issued  by  ihe  Philadelphia  Chamber  of  Commerce 


PURPOSE — To  make  Philadelphia’s  life,  industry,  history,  and  gov 
ernment  known,  understood,  and  appreciated  by  all  its  citizens. 


No.  1.  Thrift — a  short  text-book. 

No.  2.  The  Trust  Companies  of  Philadelphia. 

No.  3.  The  Rug  and  Carpet  Industry  of  Philadelphia. 

No.  4.  The  Locomotive  Industry  in  Philadelphia. 

No.  5.  Truck  Farming  in  Philadelphia  County. 

No.  6.  Candy  Making  in  Philadelphia. 

No.  7.  The  Leather  and  Glazed  Kid  Industry  in  Philadelphia. 

No.  8.  Milk  and  Its  Distribution  in  Philadelphia. 

No.  9.  Telephone,  Telegraph  and  Wireless  Systems  in  Philadelphia. 
No.  10.  The  Manufacture,  Distribution  and  Use  of  Gas  in  Philadelphia. 
No.  11.  Department  Stores  in  Philadelphia. 

Other  pamphlets  in  course  of  preparation 


